Do you agree that a household should be able to receive both loft and cavity wall insulation under GBIS?

Yes, we agree that eligible households should be able to receive both loft and cavity wall insulation under GBIS. This change will improve outcomes for residents and installers. As noted in the consultation document, fixed costs for installers, including compliance costs, are very high proportionally when only carrying out a single low cost measure. This means that it is often not viable or profitable for installers to work on the scheme, the knock-on effect of this being a shortage of installers willing to work on GBIS because many will favour more profitable schemes like ECO4.

Under the current scheme rules, a home may be need of both a loft insulation top up and cavity wall insulation, however it would only be allowed one of these measures. From an insulation perspective, this is counterproductive because about one-third of all the heat lost in an uninsulated home escapes through the walls¹. Hence, by topping up loft insulation but not carrying out cavity wall insulation at the same time, the heat loss problem will not be effectively solved because a significant amount of heat will still be lost through uninsulated cavity walls. For this reason, we support the proposed amendment to allow households to receive both loft and cavity wall insulation.

However, it is our view that this multi-measure approach should be extended to cover all eligible measures. A whole house, multi-measure approach to retrofit will always deliver the best outcomes for residents in terms of thermal comfort and energy bill savings. Moreover, while loft insulation and

cavity wall insulation are undoubtedly effective measures, there are many other insulation measures which can deliver significant energy savings for households. Even if loft and/or cavity wall insulation is installed in a home, the building may still be leaving significant amounts of heat through other building elements. For example, if a home has uninsulated solid walls, residents could be losing 45% of their heat through the walls. In addition, up to 15% of the heat in a room can be lost through uninsulated floors², while air infiltration through a sash window in good condition can be reduced by as much as 86% by adding draughtproofing³. If these major sources of heat loss are left untreated, residents will remain cold and their energy bills remain unnecessarily high, even after receiving support through GBIS. Therefore, we believe that the potential for installing multiple insulation measures through GBIS should not be limited to loft and insulation but should instead be extended to any combination of insulation measures that are recommended on a valid retrofit assessment. This will support a holistic, whole house approach to retrofit which will deliver much better outcomes for residents than a piecemeal, single measure approach.

¹ Energy Saving Trust (2024). Cavity wall insulation. Available at: How to install cavity wall insulation – Energy Saving Trust
² Kingspan (2023). A Guide on How to Insulate Your Floor. Available here: A Guide on How to Insulate Your Floor | Kingspan IE
³ Historic England (2018). Draught-Proofing. Available at: Draught-Proofing | Historic England

Do you agree that we should allow this change to be effective from the date of consultation? If not, would you prefer the change to be effective from the date of Government Response, or the commencement date of the legislation?

Yes, we agree that this change should be implemented from the date of this consultation; this will ensure that eligible households are able to benefit from the changes as early as possible.

Do you agree with allowing projects meeting the ECO4 rules to count towards an obligated supplier’s GBIS obligation?

Yes, we agree that projects meeting the ECO4 rules should be allowed to count towards an obligated supplier’s GBIS obligations. ECO4 is a more effectively designed scheme than GBIS as it supports a multi-measure, whole house approach to retrofit, whereas, as a single measure scheme, GBIS encourages a piecemeal approach to retrofit which is not best practice and does not deliver the best outcomes for residents. As well as delivering greater benefits for residents, ECO4 is a more attractive scheme for installers because its multi-measure, whole house approach lowers fixed costs and increases profit margins for installers. Importantly, ECO4 is a fuel poverty scheme, therefore allowing more projects meeting the ECO4 eligibility will enable more energy efficiency measures to be delivered to those households who need it most. The NIA believes in an approach to retrofit that prioritises the most vulnerable households, as such, we support ECO4 projects being allowed to count towards an obligated supplier’s GBIS obligation.

If implemented, it is important that appropriate safeguards are put in place to ensure that no ‘double counting’ takes place, i.e. suppliers counting one project towards both their ECO4 and GBIS annual bill saving obligations. This would result in fewer retrofit measures being delivered overall across both programmes. With so many households in fuel poverty and more money struggling with high energy bills, it is vital that there is no reduction in the number of overall energy efficiency measures delivered through both schemes.

In the long term, the Government should look to tackle the root causes of the current issues surrounding GBIS delivery to ensure that both schemes operate effectively. For example, it should allow multiple measures to be delivered to the same property through GBIS for all eligible households. This would deliver greater overall bill savings for households and reduce fixed costs for installers, thereby addressing the main reason for under-delivery on GBIS.

Do you agree with our preferred option of a transitional arrangement that enables projects that have met the ECO4 rules during all phases of GBIS to be capable of notification and therefore count towards GBIS obligations in phase A, B, or C?

Yes, we agree with this option.

Do you agree that the proportion of GBIS obligations that can be achieved via delivery under ECO4 rules should be limited? What should the limit be? Please provide as much detail as possible.

No, we do not think the proportion of GBIS obligations that can be achieved via delivery under ECO4 rules should be limited. ECO4 is a multi-measure scheme targeted at fuel poor households that delivers greater annual bill savings per household than GBIS at a lower delivery cost per ABS, as outlined in the consultation. Since ECO4 measures are a more cost-effective way to lift households out of fuel poverty, we do not think that there should be a limit on the proportion of GBIS obligations that they can constitute.

Do you agree that a conversion factor should be applied to projects meeting the ECO4 rules that count towards GBIS?

Yes, if GBIS is to remain within its overall budget of £1 billion, it makes sense to apply a conversion factor to account for the fact that it costs less to achieve the same annual bill savings through ECO4 measures. However, should delivery exceed expectations to the extent where the scheme’s budget is likely to go beyond the original £1 billion allocated from energy suppliers, the Government should remain open to increasing the scheme’s budget to ensure that all eligible and interested households are able to receive measures.

Do you agree with our estimate that the cost of achieving an ABS under GBIS would be £X/ABS with the proposed scheme changes? Do you agree that the cost of achieving an ABS under ECO4 (excluding EFG and SWI minimums) would be £Y/ABS?

Yes, we agree that the cost of achieving the same annual bill saving will be lower under ECO4. As a multi-measure scheme, fixed costs are proportionately lower on ECO4, therefore more funding is spent on delivering retrofit measures and less on administrative activities. Moreover, a whole house retrofit is more effective at delivering overall bill savings for households than a single measure scheme like GBIS which often leaves major sources of heat loss unaddressed.

We are not considering utilising TMLP for ECO4 at this time. Do you agree with our approach?

Yes, we agree with this approach as ECO4 is a multi-measure scheme which includes more complex and higher risk measures. Thus, a thorough quality assurance and risk management process such as that set out in PAS 2035 is needed to mitigate risk and protect households.

Given the structure of the version of TMLP suitable for GBIS, what are your views on the average cost assumptions for compliance with its processes (forecast at approximately £400 to £500)?

Compliance costs can vary significantly from £500 – £1200 per install. However, there is likely to be a reduction in costs for coordination and design services for TMLP procedures in light of appropriate interventions.

We understand that most companies working on single measures of this nature would likely already have either a low cost design intervention (off the shelf) or in-house resource for the simple system design for these basic interventions. That said any lodgement services that are contracted externally are charged at an industry premium and usually suffer from low supply for the pace of low cost interventions, so it would be expected that with reasonable uptake of TMLP there should be some cost saving seen by GBIS contractors.

What do you think could be the main drivers for any potential savings between the costs of compliance with PAS 2035/2030 and the costs of compliance with TMLP for GBIS?

In our opinion, the TMLP approach negates the involvement of a retrofit coordinator and qualified retrofit designer (as per PAS 2035 guidelines). Generally we understand the motivation around low cost interventions is to run installations at pace to create volume revenue returns. If it is deemed possible to achieve GBIS bankable savings by limiting the administrative time lag to a full coordination project this would be considered a small win for retrofit installers.

Ventilation interventions cannot be overlooked, but if Trustmark are truly only going to permit low risk loft insulation to be carried out, then this would be for cavity properties that likely already have some ventilation interventions already in place. If this is not the case, it is unlikely the loft insulation measure would be considered low risk due to the condition of the property.

From the perspective of a local insulation installer, the biggest cost will still be fitting electrical ventilation interventions in wet rooms with due diligence and in accordance with PAS, where these have not been applied to the property previously. Therefore, savings would largely depend how well recorded and accountable these ventilation strategies and interventions are under TMLP in comparison to PAS. Whilst it would be an administrative saving to an installer of low cost fabric measures, it could present potential risk of omission or validation should future issues arise.

In terms of heating controls, they are only likely to be processed through a PAS or TMLP procedure where it forms part of a funded route. For example, consumers that qualify for the ‘low income group’ can benefit from loft insulation with a heating control measure through GBIS. This is a very small and niche group, so whilst it would create some simple and easy wins for local contractors, the majority of heating control measures are usually taken up through able to pay offers provided by energy suppliers. Whilst they will follow building regulations and appropriate electrical testing and commissioning procedures, it is unlikely that they would take to the time lodge such installs in the TM Datawarehouse.

Are there any other changes, not proposed in this consultation, that you believe would increase levels of delivery under GBIS? If yes, please provide details.

Enabling multiple measures to be delivered under GBIS would increase the number of measures installed under the scheme. This would reduce fixed costs for installers, including compliance and administration costs, thereby enabling more of the scheme’s budget to be spent on installing retrofit measures and less on A&A activities. Taking a whole house, multi-measure approach to retrofit would also deliver greater bill savings and outcomes for individual households.

Another way to increase levels of delivery under GBIS would be to increase the number of eligible measures available to households. Specifically, we would like to see draught proofing included as an eligible measure under the scheme. For many vulnerable households, draughtiness is one of their primary concerns and without adequate draught proofing, the financial and environmental benefits of these other measures is greatly reduced. For instance, there is little point in cavity wall and loft insulation if all the property’s heat escapes through draughty windows and doors. For a significant number of UK properties, building regulations mean they are not able to benefit from many energy efficiency improvements. This is particularly true for leasehold flats and listed homes. For many of these properties, draught proofing is one of the only options available to them if they want to lower their energy bills and make their home warmer. Moreover, as draughtproofing is a low cost, high impact measure, its inclusion with GBIS would enable the scheme to deliver more insulation measures to a greater number of households using the same overall budget.

DESNZ’s cost assumption for compliance with PAS 2035/2030:2019 processes is £1,030 per property retrofit (in 2023 prices) for both ECO4 and GBIS. The assumed cost does not vary according to how many measures are installed. Roughly what is the average cost you have experienced complying with the current PAS 2035/2030:2019 processes per property retrofitted? Please answer for both multimeasure and single-measure projects that have upgraded the fabric of a building, as relevant.

For multi measure projects, between £900 and £1100 is a fair representation of market rates incurred in covering compliance with retrofit assessments, retrofit design and retrofit coordination services and lodgement. It does not include the implied administrative costs of ensuring installers and the supply chain comply with the documentation requirement. Our members have experienced a continued uptake in administrators across the sector to enable this quality side is sufficiently documented and managed correctly.

For single measure projects, we have found that a number of industry providers are able to meet the demand for design and coordination through simple in-house provision or through external companies providing services at lower rates than where an architectural intervention is considered for design. As such, we would not expect multi-measure design processes that follow correct procedures in accordance with PAS 2035 to be in similar in cost to those utilising a single measure approach under GBIS for example.

Whilst the overall approach to retrofit coordinating has parallels, it would be concerning if no further work is undertaken from a retrofit coordinator on a multi-measure project compared to a single- measure project. Due diligence in reviewing the design should be taken to ensure areas are not omitted or ignored due to cost implications. For example, where thermal bridges could occur – between floors of a property, or at DPC level, or at roof level – calculations can be undertaken by industry professionals to ensure the risk of condensation, damp or mould is not a factor. These wider cost considerations and interventions are in the spirit of the PAS2035 procedures and are further risk management that may not be part of the costing provisioned here which should be borne in mind for the benefit of the consumer.

In September 2023 a new version of PAS 2035/2030 was published. Roughly what is the average cost you would expect for complying with the PAS 2035/2030:2023 processes per property retrofitted? Please answer for both multimeasure and single-measure projects involving an upgrade to the fabric of a building, as relevant.

We believe it is too early to tell the full costs of this, as a number of details are still unclear. Whilst we will see an increase in costs, it will take time for market rationalisation as we see upskilling and high value equipment being purchased.

These costs will vary by project size and project risk scores. We would expect air tightness testing to take place to ensure that ventilation strategies for condensation, damp and mould reduction/eradication are more appropriate and accurate, especially on higher risk projects. If airtightness testing is required for all measures and Retrofit Coordinators are expected to visit the site for every property, this will increase costs.

What, if any differences, between PAS 2035/2030:2019 and PAS 2035/2030:2023 processes are driving any changes in cost?

As an industry we are seeing that PAS Standards are starting to tighten to improve quality of energy efficiency interventions, to ensure they are documented and managed for quality standards and that there is enough due process to prevent cases of consumer failure.

Appropriately qualified designers and more robust ventilation interventions are seen as the biggest increase in cost realisation in the new PAS standard. This includes, people with the correct qualifications or accreditations to carry out these duties. We expect a much more robust architectural design to consider thermal bridging and CDM risks to be part of due diligence in more

complex interventions such as solid wall insulation or Room in Roof installations, especially as these interventions are usually combined with other measures. We are also seeing an increase in cost for the requirement of air tightness testing due to costly capital outlay on equipment and the time an assessor/ accredited person spends at a property.

Whilst expecting a Retrofit Coordinator to visit site is seen as an expensive exercise it is more likely to see a better intervention rate on the area based approach. We have seen presentations of day rates of upto £500.00 for this site presence on SHDF projects.

Our concern in the lower cost measure market or where ECO funding is in place to private consumers, is that Retrofit Assessors may well be upskilled to Retrofit Coordinators, so we would hope that there would be no room for interpretation. We believe the correct PAS approach would be to expect the retrofit coordinator that visits site to be the one that oversees the project and lodges the project not just one that holds the qualification.

We would like to understand more about the compliance costs of PAS 2035/2030. Please provide details on what you feel are the key cost drivers. For example, the PAS process, the need to use qualified professionals, the need to complete paperwork to demonstrate compliance with the PAS etc.

The main costs are likely to be the cost of qualified professionals visiting site, fuel, additional paperwork and administrative costs, and air tightness testing.

Do you agree that the policy intent could be made clearer to facilitate Ofgem’s ability to reject measures which have been identified as non-compliant by TrustMark?

Yes, we agree that the wording within the ECO Order could be made clearer to ensure that Ofgem is able to more easily reject non-compliant measures.

Do you think a Chartered Surveyor continues to be suitably equipped to conduct this assessment?

Yes.

Do you agree with our proposal to update the “rural area” definition in line with theplanned ONS and Scottish Government updates?

Yes, we agree with this proposal.

If transitional arrangements are required, which transition option would you prefer?

Option A is our preferred transition option because it creates the least administrative complexity for installers.

Do you plan to participate in ECO4 and/or GBIS PFP?

As an industry trade association, we will not be participating directly in ECO4 and GBIS PFP. However, many of our members are planning to participate in PFP.

Where development time available to industry for PFP appears limited, would you favour government introducing PFP to ECO4 and GBIS or introducing PFP into any successor ECO scheme?

We would favour the Government introducing PFP to ECO4 and GBIS at the earliest possible opportunity, once the relevant legislation has been laid, and industry parties have had sufficient time to submit SMETER applications and carry out all necessary preparation for the introduction of PFP.

Do you agree with our proposal to limit ECO4 & GBIS PFP to SMETER methods? If not, what approaches do you think we should allow and why?

Yes, we agree with the proposal to limit ECO4 and GBIS PFP to SMETER methods. This can more reliably assess the effectiveness of insulation measures than metered data which can be significantly distorted by ‘comfort-taking’. There is significant evidence of comfort-taking after the installation of insulation measures, whereby residents who previously were not heating their homes to an adequate level of warmth, heat their homes to a higher temperature after the installation of insulation measures. Therefore, we support the use of SMETERS which measure the actual impact of insulation measures on the building physics and heat loss of a property independent of any changes in occupant behaviour.

Do you agree with the likely data journey we have set out? If not, how do you expect this to differ?

Yes, we agree.

Do you agree with the data collection proposals? If not, please explain your reason and proposed alternative(s).

Yes, we agree.

Do you agree with the proposed deadlines of two and 12 months of the retrofit completion date for lodging pre and post-retrofit SMETER HTC reads, respectively? If not, please explain your reasoning and proposed alternative(s).

Yes, we agree with these deadlines.

Should we require SMETER providers to lodge confidence ranges for each HTC value with TrustMark? As this would not inform scoring, what value do you think capturing this data would provide?

Yes, we believe that the Government should require SMETER providers to submit confidence ranges for each HTC value with TrustMark. This is important to ensure compliance and reduce the risk of fraudulent activity.

Do you agree with our preference for SMETER providers to upload HTC reads to TrustMark’s Data Warehouse? If not, what alternate is preferable?

Yes, we support the proposal for SMETER providers to upload HTC reads to TrustMark’s Data Warehouse.

Do you agree with our preference for TrustMark to access RdSAP-derived HTC values directly from scheme providers?

Yes, we agree with this approach. This will increase the accuracy of HTC values and reduce the risk of fraud.

If an accreditation scheme relevant to SMETERs and in-use performance is available, do you think we should require adherence to it in PFP?

Yes, should a suitable accreditation scheme for SMETER providers become available, we would support adherence to it as a requirement for ECO PFP.

If an accreditation scheme relevant to SMETERs and PFP is not available, do you think this is sufficiently mitigated by the activities of Ofgem, TrustMark, TrustMark-licensed scheme providers and the proposed activities of a third-party auditor in PFP? If not, what further activities are necessary to assure PFP in the absence of an accreditation scheme?

Yes, while we support adherence to a suitable accreditation scheme once available, in the absence of an available scheme, we believe that the combined activities of Ofgem, TrustMark, TrustMark-licensed scheme providers and the proposed third-party auditor are sufficient to mitigate risk in PFP.

Do you agree that any accreditation scheme to which we stipulate adherence in PFP should meet the criteria set out under the “Accreditation scheme(s) for SMETER providers” section? If not, what do you think we should add and/or remove from the criteria?

Yes, we agree with the criteria set out in the consultation document.

Do you agree with our preference to require GBIS retrofits to include only one of CWI, SWI, RIRI, FRI or PRI? If not, why not?

No, we do not agree with the proposed requirement to allow GBIS retrofits to include only one of the outlined insulation measures. Firstly, we believe that floor insulation and draught proofing should be added to the list of outlined insulation measures. Both forms of insulation can deliver significant reductions in heat loss. Up to 15% of the heat in a room can be lost through uninsulated floors⁴, while air infiltration through a sash window in good condition can be reduced by as much as 86% by adding draught proofing⁵. As such, the NIA believes that floor insulation and draught proofing should be added to the list of minimum measures to reflect the substantial positive impact they can have on energy efficiency and residents’ energy bills.

Secondly, as outlined in our response to Question 1, the NIA believes that households should be able to receive multiple insulation measures through GBIS. In many homes, multiple insulation measures are needed to deliver the best outcomes for residents. A whole house approach to insulation which tackles all major sources of heat loss is much more effective than a piecemeal approach where insulation is added to one building element but not others, thereby failing to sufficiently address a home’s heat loss and residents’ high energy bills Therefore, we would like to see GBIS scheme rules changed to allow whole house, multi-measure retrofits where a retrofit assessment deems this to be the best solution for a property. This would also increase the viability and attractiveness of GBIS to installers by lowering their fixed costs, hence helping to address the supply chain issues which have held back delivery on the scheme.

⁴ Kingspan (2023). A Guide on How to Insulate Your Floor. Available here: A Guide on How to Insulate Your Floor | Kingspan IE
⁵ Historic England (2018). Draught-Proofing. Available at: Draught-Proofing | Historic England

Do you agree with our preference to require ECO4 retrofits to include at least one of CWI, SWI, RIRI, FRI and PRI? If not, why not?

Yes, we agree that ECO4 retrofits should always include at least one insulation measure because a fabric-first approach to home decarbonisation is the best way to lift residents out of fuel poverty. As such, every ECO4 retrofit should include at least one insulation measure.

However, as set out in our response to Question 69, we believe that floor insulation and draughtproofing should be added to the list of insulation measures outlined in the consultation document because of their significant energy saving impact.

Do you agree with our preference to apply the same minimum requirement in ECO4 PFP as in the ECO4 main scheme? If not, why not? 

Yes, we agree with the preference to apply the same minimum requirement in ECO4 PFP as in the ECO4 main scheme.

Do you agree with our preference to allow exemptions to the minimum requirement while excluding ‘consumer circumstances’ as valid reasons for not meeting the minimum requirement in ECO4 PFP retrofits?

Yes, we agree with the preference to exclude ‘consumer circumstances’ as a valid reason for not meeting the MR in ECO4 PFP retrofits. There is a significant risk of gaming whereby parties try to access the PFP uplift without making a genuine attempt to meet the ECO4 MR.

Do you agree with our proposal to only include homes with a relevant smart meter in the eligible pool for ECO PFP?

Yes, we agree with this proposal. Given the plan to evidence PFP using SMETERS, a working smart meter will be required to make sure that PFP can be successfully implemented. As the Government notes in the consultation, 64% of homes already have smart meters, hence this would still leave a large pool of eligible households for PFP retrofits.

Nonetheless, it is important that the Government makes a concerted effort to roll out smart meters to the remaining 36% of households that do not currently have them. As the Government looks to roll out PFP more widely across other retrofit schemes in future, it is important that homes are not excluded from support because they do not have a smart meter.

Do you agree with our preference to limit PFP to properties with those characteristics set out above? If not, why not, and what characteristics should be omitted or included and why?

Yes, we agree with limiting PFP to properties where HTC reads have been proven to be accurate through the SMETER TEST project. However, the Government should look to accelerate the testing of other building types to ensure that all building types (where viable) are eligible for PFP retrofits in the long term.

Do you agree with our proposed approach to complementary insulation work?

Yes, the NIA agrees with the proposed approach to complementary insulation work. Ancillary work that addresses existing defects or improves existing elements should be encouraged wherever possible to improve the overall thermal efficiency of homes.

We support retaining the Building Fabric Repair (BFR) uplift in ECO4 PFP, however we believe that this should be extended to GBIS retrofits too. It is crucial to ensure that any building fabric defects are properly addressed before carrying out additional works; this is crucial to the success of a retrofit project. As such, remedial works should also be encouraged on GBIS where any defects are identified. If defects remain unaddressed, this could significantly reduce the effectiveness of any subsequent insulation measures.

Do you agree with our preference to align scoring in both ECO4 and GBIS PFP with the wider ECO4 and GBIS scoring systems, respectively? What changes do you think we should make to this, if any and why?

Yes, we agree with this approach. This will avoid adding undue administrative complexity which may hinder the scheme’s deliverability.

Do you agree with our proposals to align ECO4 and GBIS PFP evidencing with the approaches in the respective main schemes? If not, why and what alternative do you suggest?

Yes, we agree with the proposal to align ECO4 and GBIS PFP evidencing with approaches in the main schemes.

Do you agree with our proposal to provide a PFP minimum score via the uplift? If not, please explain why?

Yes, we agree with the proposal to provide a PFP minimum score via the uplift because is important that suppliers are incentivised to participate in PFP. The RdSAP methodology is limited and based on numerous assumptions which may lead it to overestimate the impact of retrofit measures even when they are installed correctly. Suppliers should be incentivised to use SMETER monitoring because it is a more accurate method of measuring a retrofit measure’s ‘true’ impact, even if this results in a lower HTC improvement than using RdSAP.

Do you agree with the score outcomes we have set out in those scenarios in table 5? If not, why? In what other scenarios should we clarify PFP score outcomes?

No, as outlined in our response to Question 69, if a home receives floor insulation or draught proofing, it should still be eligible for a PFP uplift in both ECO4 and GBIS. These are both very effective forms of insulation which can significantly reduce heat loss and household energy bills when installed.

Do you agree that anomalous HTC reads should still be lodged by SMETER providers with TrustMark? If not, please explain why.

Yes, we agree that anomalous HTC reads should still be lodged with TrustMark.

Do you agree with the overall uplift approach we have proposed for PFP? If not, why not and what alternative do you suggest?

Yes, we agree with the overall uplift approach proposed for PFP. As noted in the consultation, SAP often overestimates HTC improvement, therefore it is important to provide generous uplifts so that suppliers still have an incentive to participate in PFP even when the SMETER-monitored HTC improvement is less than that modelled by SAP.

Do you agree with the uplift rates we have suggested for both ECO4 and GBIS PFP? If not, please provide data to e.g. justify any costs not covered.

We broadly agree with the uplift rates proposed for both ECO4 and GBIS PFP. As GBIS is currently a single measure scheme, it makes sense to provide a lower uplift rate. However, as previously stated, we would like to see to the GBIS scheme guidance amended to allow multiple insulation measures to be installed, where recommended as part of a retrofit assessment. Should the Government implement this recommended change, then GBIS uplift rates should be increased accordingly for multi-measure retrofits.

Do you agree with our proposal to allow the IM uplift for all eligible IMs where these are delivered in PFP? If not, why not?

Yes, we agree that the IM uplift should be allowed for all eligible IMs delivered in PFP as the IM route is an important mechanism for supporting innovation within the industry. Moreover, in some cases, innovative measures are not scored fairly within SAP, hence PFP may offer an opportunity for them to receive a greater uplift that is more representative of their ‘true’ potential for heat loss reduction.

Do you agree with our proposal for a 10% cap on GBIS and ECO4 PFP with all retrofit score contributing to this? If not, what do you propose and why?

Yes, we broadly agree with a 10% cap on GBIS and ECO4 PFP as we recognise the need to ensure that it works effectively before rolling it out more widely. However, we would like to see an annual review of this 10% cap level, whereby DESNZ and the scheme administrator review monitoring and evaluation data on a yearly basis to assess the effectiveness of SMETER monitoring and PFP. Should this annual review show that PFP is operating effectively, the cap should be raised to allow more PFP retrofits to take place. Ultimately, the Government’s long term goal should be to score as many government- funded retrofits as practicably possible using PFP because it is a more effective assessment of a measure’s in-use performance than SAP and RdSAP. It will also incentivise quality improvements across the retrofit industry.

Do you agree with the policy linkages positions we set out between the PFP mechanism and main schemes? If not, please state which you disagree with and why. What other policy linkages should we provide information on?

Yes, we agree with the policy linkages positions set out.

Click here to download the full document. 

BS 40104 Retrofit assessment for domestic dwellings – Code of practice

General Comments

• Quality and consistency of retrofit assessments. This new code of practice should improve the quality and consistency of retrofit assessments across the industry. This is welcome considering the variable quality of assessments being carried out currently. A more detailed and accurate retrofit assessment should increase the standard of retrofit work carried out and reduce the risk of harm to properties.
• Implications for the cost and time associated with retrofit assessments. Whilst we welcome a drive to improve standards, the complexity of the new requirements and their potential cost implications are a concern. It is likely that this new code of practice will increase the cost of delivering retrofit assessments significantly. There is a risk that the rising cost of compliance may become a barrier to retrofit projects or contractors working on specific schemes. The new guidance will also significantly increase the time it takes to carry out retrofit assessments. This means that a larger retrofit assessor workforce will be required just to maintain current levels of delivery. The industry will need to significantly ramp up delivery of retrofit projects in order to meet the Government’s fuel poverty and net zero targets. If retrofit assessments become overly complex and costly for the industry to carry out efficiently, then this required scale up in delivery will not be achievable.
  It would be useful to know if an impact assessment has been conducted on the additional cost to businesses in the sector of complying with this code because it is vital that this is not prohibitive for retrofit businesses. Ultimately, the code of practice should seek to balance the clear need to improve the quality of retrofit assessments with the practicality and cost implications for businesses of increased complexity. If more stringent requirements are introduced, it is critical that businesses are properly supported with the costs of compliance.
• Transition period. The code of practice does not mention a transition period anywhere. There needs to be more clarity on the length of the transition period, when the code will come into effect, and how this will fit in with PAS 2035:2023. In order to comply with this new code of practice, the existing retrofit assessor workforce will need to undergo significant upskilling, while training courses may also need to be updated to align with the new code. It is important that the transition period accounts for these factors. Therefore, a lengthy transition period is necessary for the industry to adequately prepare for the introduction of these new requirements.
• Mandatory requirements or optional guidance. Throughout the document, “should” is used rather than “shall”. In PAS 2035, normative requirements which are mandated are referenced with “shall”, while optional guidelines are referenced as “should”. The document’s use of “should” suggests that this is optional guidance, however it needs to be clearer within the code what is mandated and what is best practice.
• Project manager and retrofit coordinator. The code of practice references the “project manager” in several cases. We assume that this relates to the retrofit coordinator role, however this is unclear as the code never mentions a retrofit coordinator. Given that the code is designed to supersede clauses 7.3 and 7.4 of PAS 2035, it would be clearer if the wording “retrofit coordinator” was used, as the designated role referenced within PAS 2035.
• Different levels of retrofit assessment. One option to mitigate cost and complexity concerns would be to permit different levels of retrofit assessments depending on the funding scheme or scope of the retrofit project. The code of practice proposes a very detailed in-depth property survey which is very useful when it comes to a deep, whole-house retrofit like those carried out under SHDF. However, for GBIS which is primarily a single-measure scheme, a retrofit assessment to this level of detail may not be necessary or cost-effective. For instance, a full retrofit assessment in line with this code of practice before carrying out a loft insulation top-up under GBIS would add significant cost and complexity to the retrofit project. If another level of retrofit assessment is introduced which is less complex than this code of practice, it should still be more comprehensive than the current retrofit assessment guidance. In this way, there would be no reduction in the standard of retrofit assessments.

Equipment (Section 4.2)

Retrofit assessors may not be familiar with all of this equipment or competent in how to use it effectively. There should be a section in the Annex explaining the equipment in detail and outlining where retrofit assessors can undergo additional training in its use (if required). This should outline the purpose of each piece of equipment (including what will it be used to measure or identify) and guidance on how to use it. It should also stipulate the standard of equipment required, as this could affect the accuracy of the results.

Context assessment (Section 5.1)

The context assessment is defined as a preliminary desktop assessment but is very broad and detailed in scope. For most government-funded schemes, a significant percentage of retrofit assessments are completed that, for a variety of reasons, never progress to an actual project. As such, the requirement for a highly detailed upfront desktop assessment will add delivery cost to existing retrofit schemes. Some aspects of it might not be necessary given that an in-depth site assessment will be carried out a later stage, hence an overly detailed desktop context assessment might duplicate effort and add unnecessary additional costs. Some of the activities within this context assessment and other sections of the code could potentially be completed after measures have been specified for a property to avoid wasting time and resources on assessments that do not progress to installation stage.

Condition assessment and condition rating (Section 6.1.1)

The content of this condition assessment seems closer to that of a Level 3 RICS Home Survey than the current retrofit assessment requirements. In practice, it is likely that many retrofit assessors will default to Option c) because they lack the specialist construction knowledge or data to make an informed decision on whether defects need addressing or not. Current retrofit assessors will not always have the expertise to follow ‘the trail of a defect’ and identify its root cause. In many cases, the root cause of a defect is often impossible to determine without an intrusive survey.

A thorough retrofit assessment might save time and money in the long term, as comprehensive data collection at this stage may reduce the number of additional site visits and further investigation that are required at later stages of the retrofit project. Within PAS 2035, there are a number of other surveys and inspections that need to take place. It is important that there is no duplication of effort between the code of practice and these other surveys. In order to realise the potential for efficiencies later on in the retrofit process, it is important that the results of the condition assessment and other surveys are shared with other relevant stakeholders working on the retrofit project.

A background ventilation assessment is a complex requirement which is beyond the competency of many retrofit assessors. This should be carried out by a qualified and competent specialist.

Occupancy assessment (Section 6.3.1)

The stated purpose for an occupancy assessment is so that ‘the project manager can adjust predicted energy savings from retrofit measures’ to take account of factors such as occupancy patterns, energy use and tariffs. However, it will be very challenging to collect all of the data required for a full occupancy assessment. Many households will not have data on their energy use and tariffs over the previous 12 months easily to hand, while the innovative and fast-moving market for tariffs will further complicate efforts to accurately gather this data. Moreover, an interview with the residents may not be possible in all cases. Some tenants may not be able or willing to fully partake in an interview. Conducting an interview during every retrofit assessment could significantly increase the time and cost associated with carrying one out.

This code of practice stipulates that an occupancy assessment is required as part of every retrofit assessment. However, the imminent introduction of RdSAP10 means that there will be no formal methodology for conducting occupancy assessments, or software approval mechanism. This is likely to lead to a lack of consistency across assessments.

An occupancy assessment is useful for certain purposes, such as:

• Helping the retrofit coordinator to calculate payback periods;
• Assessing moisture management which will influence ventilation requirements;
• Identifying operational defects.

However, the additional insights gained from such a detailed occupancy assessment may not be worth the additional time and effort invested in it. At the moment, very few retrofit designs consider the results of occupancy assessments, as there are not many energy efficiency measures that would be impacted by the outcome of an occupancy assessment.

Assessor competencies (Annex C)

The scope of the retrofit assessor role and what they are capable of needs to be considered carefully. Some of the activities here seem to overlap with the work of the pre-installation building inspection (PIBI) and could potentially be covered within that. Other aspects require a high level of general construction knowledge which not all retrofit assessors may have, particularly those who do not come from a construction background.

The existing retrofit assessor workforce does not currently possess all of the competencies outlined in Annex C, hence a substantial upskilling and retraining of the current retrofit assessor workforce will be needed to implement it effectively. Therefore, this code of practice should be accompanied by a concerted drive to improve the training and competency of the existing retrofit assessor workforce so that it is sufficiently prepared for its introduction. This should include increased funding and support for businesses to train and upskill employees.

Qualifications (Annex D)

The level of detail within this code of practice is beyond the current content of many retrofit assessor training courses. Therefore, many existing training courses will need to be improved to align with this new code of practice.

Summary – SHDF Wave 3 Draft Guidance

The Social Housing Decarbonisation Fund (SHDF) provides energy efficiency measures to social housing across England. Wave 3 will run from April 2025 to September 2028, and will provide social housing providers with £1.2 billion of government funding to retrofit their housing stock. You can read the draft guidance in full here.

Headline proposals

• There are two new routes to access funding under Wave 3, via the Challenge Fund and via Strategic Partnerships.
• Wave 3 includes a cost cap of £7,500 of grant funding per home. This cap can be averaged across homes in an application (including across different consortium members).
• There is also an additional £7,500 grant funding cost cap for low carbon heating measures in homes off the gas grid.
• There is a new optional low carbon heating incentive for homes on the gas grid. Up to 10% of homes in an application can gain access to a £20,000 grant fund per home to install low carbon heating measures on the gas grid (instead of the usual £7,500 on the gas grid cost cap).

Main changes from previous waves

Delivery window

The Wave 3 delivery window will run until 30th September 2028. All grant funding for SHDF Wave 3 projects must be transferred to the Grant Recipient and spent by 31st March 2028, and within the financial year the grant funding was allocated, meaning projects can only use co-funding in the final 6 months of delivery.

Project grant funding spend must be aligned to the SHDF spend profile of 40% in FY25/26, 40% in FY26/27 and 20% in FY27/28.

Performance outcomes

Grant Recipients are expected to get homes to EPC C, however DESNZ accept that there may be circumstances where this is not achievable within the cost caps. If this is the case, homes are expected to attain the maximum EPC grade achievable within the cost caps. The 90/kWh/m2/year space heating demand consideration in Wave 2 no longer applies for Wave 3.

Homes which cannot reasonably reach EPC C within the cost cap are exempt from this requirement. However, at Phase Request stage, Challenge Fund Grant Recipients must demonstrate why it would cost over £15,000 to get the home to EPC C).

Cost caps

There is a new single cost cap for energy efficiency measures which is consistent across all homes and does not vary by starting EPC band or wall type as it did in Wave 2. The Wave 3 cost cap is £7,500 of SHDF grant funding from the Government per home. In addition to this government funding, social housing providers must provide a minimum of 50% co-funding. This means that the average capital spend per home will be £15,000 for the installation of fabric efficiency measures (assuming 50% co-funding).

This cap can be averaged across homes in an application (including across different consortium members). Therefore, it is possible for applicants to spend more or less than £7,500 of grant funding per property, as long as the average amount of grant funding spent across an application is less than or equal to the £7,500 cost cap.

In Wave 3, there are also additional cost caps for low carbon heating measures, which are outlined in more detail below.

Additional off gas low carbon heating cost cap

There is an additional £7,500 grant funding cost cap for low carbon heating measures in homes off the gas grid. This will be available in addition to the baseline £7,500 energy efficiency cost cap and can also be averaged out across homes. This means that applicants will be able to access a total of £15,000 of SHDF grant funding from the Government for off gas homes, split into 50% for energy efficiency measures and 50% for low carbon heating. When combined with 50% co-funding, this means that applicants will be able to spend £30,000 per property on off gas homes.

New Wave 3 on gas grid low carbon heating incentive offer

Wave 3 includes a new low carbon heating incentive for on gas grid homes. For up to 10% of the homes in an application, applicants will be able to access a grant of £20,000 per home. The entire £20,000 will come from the Government’s SHDF funding, so there is no co-funding requirement. For homes making use of the £20,000 incentive offer, installation of low carbon heating is mandatory. It is expected that the £20,000 is also used for energy efficiency measures to ensure that bills do not go up.

The only heating systems eligible for this offer are:

• Air source heat pumps
• Ground source heat pumps
• Shared ground loops
• Heat networks.

Summary

Table 1 below provides a summary of the different cost caps operating within SHDF Wave 3.

Eligible measures

Any energy efficiency and heating measures compatible with SAP are eligible under SHDF, excluding systems solely powered by fossil fuels. However, only a limited number of heating systems are eligible for new £20,000 on gas grid low carbon heating incentive offer. Heating systems eligible for this incentive are listed in Section 4.2.

• Solid biomass. Whilst solid biomass is an eligible measure, this is only expected to be installed in exceptional circumstances where heat pumps are unsuitable for the dwelling, and only in rural areas where there are no air quality restrictions.
• Hybrid heat pumps. Hybrids are an eligible measure for homes currently heated by mains gas, however they are not permitted in homes off the gas grid.
• Smart technologies. SAP-eligible technologies which would enable Smart Meter Enabled Thermal Efficiency Ratings (SMETER) (such as smart thermostats) are an eligible measure.

Revisiting homes

Homes previously treated in SHDF Wave 1 or the SHDF Demonstrator are eligible to be treated in SHDF Wave 3 as long as they comply with SHDF Wave 3 eligibility requirements and only where installing low carbon heating measures. Homes treated in SHDF Wave 2 are not eligible.

Minimum number of homes

Wave 3 Challenge Fund applications must include a minimum of 100 eligible social housing properties at EPC band D-G per application. Small social housing landlords (those who own or manage fewer than 1000 homes) can apply with fewer than 100 homes. Strategic Partnership applicants will be expected to propose projects of significant scale, which retrofit thousands of homes.

Application timelines

Eligible properties

All social housing below EPC C is eligible for SHDF Wave 3 funding, apart from homes already retrofitted during Wave 2 of SHDF.

Homes at EPC C or above

In previous Waves of SHDF, homes already at or above EPC band C could only be included on an infill basis. In Wave 3, this is still the case, but there is also another instance whereby homes at EPC C or above can be included. This applies to homes where low carbon heating measures are being installed. In both instances, applications are limited to a maximum of 10% of all homes within the bid being at or above EPC band C.

Infill

Where a small number of properties in a block or terrace are at EPC Band C or above, they can be included in bids where work to those properties enables effective works to social housing below EPC Band C. Challenge Fund Applicants must justify this approach in Phase Requests, including providing the % of properties at EPC Band C or

above. There would need to be a significant reason for inclusion of these properties – any application without appropriate justification will not be successful.

This infill funding can only be used to install insulation, ventilation and low carbon communal heating.

Low carbon heating measures

Homes at or above EPC band C are eligible for the installation of low carbon heating measures. This applies to homes accessing the off-grid low carbon heating cost cap, or the on-grid low carbon heating incentive.

Mixed tenure and non-social homes

Private homes may be eligible for funding under the Wave 3 infill policy on non-social homes. Shared ownership homes also fall under the scope of Wave 3 infill policy.

Infill of non-social homes can only apply:

• In a situation where social homes would be adversely affected without it, for example cases where social homes would not be able to meet EPC C without works taking place on non-social homes, or where works must be undertaken on a whole block for planning or logistical reasons.
• To a maximum of 30% of the homes in the application bid.
• To insulation, associated ventilation, and communal low carbon heating measures.

The requirement for owner occupiers and private rented sector landlords/tenants to contribute to measure costs that applied in previous waves of SHDF no longer applies.

Mixed tenure blocks and terraces are eligible for SHDF funding. In any block/terrace being treated, at least 30% of the homes within the block/terrace must be social homes.

Installers

All installers of energy efficiency measures under SHDF must be TrustMark Registered, certified to MCS (or equivalent) for the technology they are installing. All projects must be compliant with PAS 2035/2030:2019.

Administration and Ancillary Costs (A&A)

A&A costs are expected to be as low as possible, with a requirement that grant funding for A&A comprises no more than 15% of total grant spend by the end of the project.

Interaction with other energy efficiency schemes

Applicants may use funding from other government schemes, such as the Energy Company Obligation (ECO), to support works on the same home but funding from multiple government schemes cannot be used to fund the same individual measure twice.

Retrofit information, support and expertise

Technical assistance for SHDF Wave 3 will be delivered under the name of ‘RISE’ – Retrofit Information, Support and Expertise – through Turner & Townsend.

The Department for Energy Security & Net Zero (DESNZ) expects that Applicants will inform RISE about their intent to apply for SHDF Wave 3. Applicants can do so via the self-assessment form found at www.riseretrofit.org.uk or email rise@turntown.co.uk.

Application Routes

Challenge Fund

The vast majority of applicants are expected to access funding via this route. All Challenge Fund applications that meet the minimum standards of the scheme will be awarded funding (although if oversubscribed, this may not be the amount of funding requested).

Applications are assessed against the following criteria:

• Strategic fit: an assessment of how well the proposal fits with the aims, desired outcomes and eligibility criteria of the SHDF Wave 3 Challenge Fund.
• Delivery forecast: an assessment of the plan for the project, including proposed costs.
• Commercial assurance: an assessment of the feasibility and credibility of the approach to procurement as well as of the proposed contracts required to move to Phase Request stage.
• Delivery assurance: an assessment of the feasibility and credibility of the project including resource; project management strategies; risk and issues management and confidence in delivery of the project.

The phase approach

The Challenge Fund model will be delivered according to a phased approach, whereby groups (or batches) of homes are submitted to DESNZ in phases. Each phase will cover all or a proportion of the homes within a project. DESNZ expects that no project will have more than 10 phases or less than 10% of total homes in any one phase.

Before measures are installed in any homes, a Phase Request covering those homes must be submitted to and approved by DESNZ. The information in each Phase Request should be based on a significant number of completed retrofit assessments to ensure confidence in the accuracy of the information provided. DESNZ suggests that this should cover c.70% of flats in a block, or c.90% of homes where they are spread out.

Applicants will not be required to provide detailed information on specific homes and measures at the initial application stage. Instead, they will simply need to demonstrate that they will be able to deliver a project to the required specifications. More detailed information on homes is required only when applicants submit Phase Requests. Applicants must quantify the mix of measures they are intending to install at Phase Request stage and why they are the most suitable measures.

Figure 1 below sets out the application and delivery process for the Challenge Fund.

Assessment of Phase Requests

Phase requests will be assessed by DESNZ according to the following criteria:

• Strategic fit: an assessment of how well the proposal fits with the aims, desired outcomes and eligibility criteria of the SHDF Wave 3 Challenge Fund.
• Contractor procurement: An assessment of the suitability of the contractors that have been procured for delivery of this phase.
• Delivery assurance and internal resourcing: an assessment of the feasibility and credibility of the project, including organisational design, fraud management and planning.
• Delivery forecast: an assessment of the proposed activities and spend to take place each month.
• Value for money: an assessment of the costs of the proposed measures to be installed, a cost breakdown of the phase and a justification for the cost of the phase.

If a phase request is approved, applicants will be allowed to start delivery on that phase of homes. If it is rejected, applicants will be directed to further and asked to re-submit after making changes.

Payment of the grant

In the Challenge Fund route, Lead Grant Recipients will only be able to draw down up to 20% of their total grant funding award before their Phase Requests are approved; made up of 15% A&A and 5% capital. They will be able to draw down the remainder of the grant following the approval of Phase Requests.

Strategic Partnerships

A small number of Grant Recipients with a proven track record of successful delivery at scale (1000s of properties) can access funding through a Strategic Partnership. To reflect the capability evidenced by these landlords and to support delivery at scale, these Grant Recipients will not be required to provide detail on specific homes and measures until works have been carried out, as part of routine delivery monitoring.

To be eligible for a Strategic Partnership, the Lead Applicant must have delivered on the SHDF Demonstrator, Wave 1, and Wave 2.1 or Wave 2.2, either as the Lead Grant Recipient or as part of a consortium.

Strategic Partnership Applicants will be expected to propose projects of significant scale, retrofitting multiple thousands of homes.

Application process

The application process for Strategic Partnership applications will place a reduced focus on specific project detail and a greater emphasis on evidence of delivery capability.

Strategic Partnerships, applications will be assessed on how well they meet SHDF’s four, equally weighted, strategic priorities. There are up to 10 points available for each strategic priority, so applications which deliver on a greater number of priorities are potentially able to score more highly, but applications that do not deliver on every strategic priority will not be automatically ruled out.

The four strategic priorities are listed below:

Strategic Partnership Lead Applicants will be informed of the outcome of their application before the closure of the Challenge Fund application window. Therefore, any unsuccessful Strategic Partnership Applicants will still have the opportunity to submit an application to the Challenge Fund if their Strategic Partnership application is rejected.

At initial application, Challenge Fund Applicants will not be required to provide information on specific homes to be upgraded or specific measures to be installed. Instead, Applicants will be asked for information to demonstrate that they will be able to deliver a project to the required specifications.

Click here to download the full document. 

The Home Energy Model: Future Homes Standard Assessment

The Home Energy Model (publishing.service.gov.uk)

Closing Date: 27 March 2024
Response submitted by: National Insulation Association
For more information, please contact: info@nia-uk.org

About the National Insulation Association
The National Insulation Association (NIA) represents the insulation industry in the UK with a member base comprised of installers, system certificate holders, and manufacturers who provide a wide range of insulation solutions for homes and buildings. The NIA and its members are fully committed to maintaining and raising standards within the insulation industry.

What are your views on the choice of name for the new model? Please provide your reasoning and any supporting evidence.

We are satisfied with the choice of name.

What are your views on the choice of name for the version of the model which is to be used to demonstrate compliance with the Future Homes Standard? Please provide your reasoning and any supporting evidence.

We are satisfied with the choice of name for the FHS assessment version of the HEM. It makes sense to include specific reference to the FHS, as this makes it clear what the model’s application will be and distinguishes it from the underlying model.

What are your views on using the open-source code as the approved methodology for regulatory uses of the Home Energy Model? Please provide your reasoning and any supporting evidence.

The NIA welcomes the move to publish the open-source code, as this will aid transparency and promote greater understanding of the methodology among relevant stakeholders. It will also give industry experts the chance to scrutinise the code and suggest improvements or raise any potential concerns. This should improve the overall effectiveness of the model.

If the open-source code is used as the approved methodology for regulatory uses of the HEM, we would like to see more clarity and guidance on what the process will be for dealing with errors in the code, in particular around liability and the transfer of risk. If there are errors with the centralised code, it is important that risk and liability is not transferred onto individual software providers who use the code as a basis for producing EPCs and determining compliance with building regulations. It is also important to avoid a situation whereby errors in the code become embedded into law.

It is important that making the open-source code the legal basis for the methodology does not act as a barrier to making necessary changes to the model in a swift manner. It must be possible for the HEM to be constantly improved and refined to improve its effectiveness. There is the potential that a codebase underpinned by regulation will be very slow to change. It is important that this does not act as a barrier to regular updates and improvements to the model. As mentioned earlier, if there are errors in the code, it is vital that these are rectified as soon as possible, without the need for a long, drawn-out regulatory process.

Whilst we agree with publishing the open-source code, it is important that other documents are published alongside it so that people not familiar with Python are still able to understand the methodology behind the model. It is encouraging to see that the Government will be publishing accompanying technical documents to provide further explanation about the model. This will ensure that the methodology is accessible to a wider range of people, thus aligning with the Government’s objective to make the HEM more transparent.

What forms of collaboration would you be interested in for future development of the Home Energy Model codebase? Please provide further details.

There must be a clear process for managing, evaluating and updating the codebase. It is important that industry is involved in this process so that they can shape the future development of the codebase.

What are your views on our assessment of issues with the current SAP delivery model? Please provide your reasoning and any supporting evidence.

We agree with the issues outlined with the current delivery model, however it is unclear how the HEM will resolve all of these, in particular the inertia of the SAP methodology. If the codebase is embedded in regulation, this could complicate and slow down the process of making changes to the methodology. Introducing a centralised, cloud-based version of the code has the potential to enable quicker updates to the methodology. However, it is not entirely clear how this would operate in practice and what the relationship would be with accompanying regulations.

Lack of accountability is a key issue, however it is still unclear from the consultation proposals where the balance of accountability will lie with the HEM. We would welcome clarity on who will be accountable, whether this be the Government, BRE, or independent software providers. If the Government proceeds with a centralised, cloud-based version of the HEM, this could simplify the issue of accountability.

At the moment, different software providers all have differing versions of SAP which can cause inconsistencies in results, although these tend to be small. Having a centralised, standardised code should help to minimise these inconsistencies in results. It should also help to clarify the accountability of different parties by providing one consistent version of the ‘truth’.

What are your views on the concept of a centralised, cloud-based version of theHome Energy Model, to be used for regulatory purposes? Please provide your reasoning and any supporting evidence.

We agree with the concept of a centralised, cloud-based version of the HEM. Currently, different software providers have differing versions of SAP which can lead to inconsistencies in results. Centralising and standardising the model will help to increase accuracy and minimise these inconsistencies. The ability to make quick updates to the central platform is key.

It can be unclear where the balance of accountability lies with the current version of SAP, whereby different software providers implement differing versions of the methodology independently. Having a centralised, standardised model will help to clarify where accountability lies and transfer risk away from software providers. It is important that it is clear which body is ultimately responsible for the HEM (whether this be BRE or the Government).

The provider of the centralised model (BRE for example) will need to understand and put in place appropriate support arrangements to allow independent software providers to easily build user interfaces around the central platform.

What are your views on revising the database of product characteristics (currently the “PCDB”) for the Home Energy Model? Please provide your reasoning and any supporting evidence.

We agree with the intention to revise the database of product characteristics for the Home Energy Model. It is important that the PCDB is based on accurate and up-to-date data, and includes the most effective technologies currently on the market.

What changes would you recommend to the PCDB data collection procedures? Please provide your reasoning and any supporting evidence.

It is costly for manufacturers to get their products listed in the PCDB. This prohibitive cost means that many products are not listed on the database because it isn’t worth the effort and cost for manufacturers to apply for their products to be listed. The process should be streamlined and made more cost-effective for manufacturers, as the cost of getting products listed is a significant barrier for many.

What are your views on our assessment of issues with the way SAP currently recognises new technologies (currently the “Appendix Q process”)? Please provide your reasoning and any supporting evidence.

We agree with the issues identified around the Appendix Q process. In general, the process is too costly and time-consuming which can act as a barrier for new innovative products being recognised via SAP. The HEM must make it easier for innovative new products to become recognised.

What are your views on the principles for how the Home Energy Model will recognise new technologies once it is in use? Please provide your reasoning and any supporting evidence.

We support the principles set out in the consultation for the how the HEM will recognise new technologies. However, more detail is needed on how the process will work in practice. The reformed Appendix Q process should focus on reducing the cost burden and length of time that it takes for innovative technologies to gain recognition, as this can prove a significant barrier to new innovations entering the market and becoming commercially viable. Ultimately, the HEM needs to enable innovation rather than hinder it.

The opportunity for continuous evaluation should enable regular “live” updates to the HEM which may make it easier and quicker for new, innovative technologies that come onto the market to be recognised by the HEM. Greater integration with other innovation routes such as ECO4 is welcome to avoid the need for companies to duplicate unnecessarily a process which can be costly and time-consuming. More detail is required on how this integration will work in practice.

The ability of innovative technologies to become recognised within SAP also depends on the underlying measurement standard. If the underlying standard is not broad enough to cover innovative technologies, then it is difficult for them to be introduced.

What are your suggestions for other wrappers that could be developed for the Home Energy Model in future? Please provide your reasoning and any supporting evidence.

The proposals identify the main wrappers that should be included within the HEM, excluding the very important EPC wrapper which will be consulted on later this year. In general, we welcome the use of wrappers, as they should improve on the SAP process, however, the HEM’s modelling will only be as accurate as the data inputted into it, therefore it is important to choose the most suitable wrappers to achieve more accurate and reliable outputs.

The effectiveness of wrappers depends on how straightforward it is to interact with the core engine and what controls will be on it. At the moment, it is unclear how open the interface will be and how easy it will be to implement new wrappers. If it Is easy to add new wrappers and build software interfaces, then the wrapper system has the potential to be a lot more efficient than the current system, which can make producing an EPC quite a time-consuming and laborious process. If the wrapper process is efficient and accessible, it should be possible to quickly produce an output wrapper, whereas in SAP it can take hours to manually write up a report.

What are your views on the increased time resolution offered by the Home Energy Model? Please provide your reasoning and any supporting evidence.

The NIA welcomes the increased time resolution offered by the HEM. This will increase the accuracy of the HEM compared to SAP and bring a range of other benefits including:

• More accurate modelling of heat pump performance and importantly the interaction with other building elements within the whole building system.
• Better alignment of the HEM with improvements in real-time monitoring and evaluation of building performance. Enabling these improvements to be reflected within the model will enhance its accuracy and help to close the performance gap.
• More recognition of the benefits of smart technologies and the importance of energy flexibility.

Despite the clear benefits of increasing the time resolution, we are concerned by the longer runtime of the HEM which has been identified as an issue by the Government. Industry urgently needs more detail and clarity on exactly how long the expected runtime of the HEM will be. It is very important that the HEM still has a reasonable runtime that does not make the model impractical to run. For instance, a runtime of 5 minutes, although not ideal, would most likely still be workable for industry. By contrast, a runtime of 15 minutes or more would represent a substantial challenge for SAP users and would significantly reduce the effectiveness of the HEM in practice.

What are your views on the choice of BS EN ISO 52016-1:2017 (in its half-hourly
form) as the basis for the Home Energy Model? Please provide your reasoning and any supporting evidence.

The move to BS EN ISO 52016-1:2017 which is a recognised industry standard seems reasonable. There are clear benefits associated with moving to a standard that supports the HEM’s half-hourly simulation.

What are your views on the ability of the Home Energy Model to model energy flexibility and smart technologies? Please provide your reasoning and any supporting evidence.

The half-hourly time resolutions of the HEM gives it the potential to model energy flexibility much more accurately than SAP.

The usefulness of the HEM for modelling energy flexibility depends on the range of applications it is used for. The existing SAP methodology focuses on the building as an asset and ignores the occupants and their energy consumption habits in favour of standardised assumptions. The HEM’s potential for modelling energy flexibility is unlikely to be relevant when assessing a building’s compliance with building regulations for example, as this is solely based on the building’s performance as an asset. Energy flexibility is dependent on energy suppliers and occupants which is largely out of the control of developers and retrofit contractors.

It is clearly useful to have a model that can take into account energy flexibility and the use of smart technologies, particularly as these start to become more commonplace in homes. It is important to have a model that is responsive to changing patterns of energy consumption and the increased energy flexibility that smart technologies can bring for residents. However more detail is required from government on how it intends to use the HEM’s potential capabilities around energy flexibility and smart technologies. For instance, this could be used to model custom energy demand.

What are your views on the methodological approach for calculating space heating and cooling demand? Please provide your reasoning and any supporting evidence.

We support the methodological approach for calculating space heating and cooling demand. The new approach, as well as the use of more detailed inputs, will model the space heating demand of buildings more accurately than SAP. It is possible that it will lead to a higher space heating demand calculation than SAP, which will incentivise greater reductions in energy demand through increased fabric efficiency.

What are your views on the methodological approach for calculating fabric heat loss? Please provide your reasoning and any supporting evidence.

We agree with this approach.

What are your views on the methodological approach for calculating thermal bridges? Please provide your reasoning and any supporting evidence.

We agree with this approach.

What are your comments on the methodological approach for calculating infiltration and/or controlled ventilation? Please provide your reasoning and any supporting evidence.

We agree with the methodological approach for calculating infiltration. This should increase accuracy because it takes into account more factors and uses wind speeds updated on an hourly basis, making it much more receptive to changes in weather conditions. The omission of other contributing factors such as wind direction and “stack effect” from the HEM are unlikely to have a significant effect on the accuracy of the modelling. However, we would support their future inclusion, along with any other updates which increase the granularity and accuracy of the modelling. We also support replacing the fixed minimum dwelling ventilation rate with a wrapper input value as this will make the modelling more dwelling-specific.

What are your views on the methodological approach for calculating thermal mass? Please provide your reasoning and any supporting evidence.

We welcome the approach to include the entire building envelope within thermal mass calculations. This should produce a more accurate calculation than SAP 10.2 which only takes part of the construction envelope into account. Including warm up and cool down rates will also increase accuracy compared to the current approach based on a one-off, instantaneous value which doesn’t reflect how buildings warm up and cool down in practice.

While we support the desire to be as accurate and dwelling-specific as possible, we do not agree with the proposal to include the thermal mass of furniture in thermal mass calculations. Many properties, especially in the non-domestic sector, are unfurnished. It is not clear how the current approach would account for unfurnished properties. Furthermore, it doesn’t make sense for furniture to be taken into account when determining a building’s SAP rating or compliance with building regulations. This is often out of the control of developers and may depend on the personal choices of residents. We do not think that the negligible increase in accuracy that including furniture in thermal mass calculations will bring outweighs the issues that this approach may create.

What are your views on the methodological approach for calculating solar gains and solar absorption? Please provide your reasoning and any supporting evidence.

We support the approach for calculating solar gains and solar absorption, as it should provide more accurate results than the current version of SAP.

What are your views on the methodological approach for calculating heat losses from Domestic Hot Water pipework? Please provide your reasoning and any supporting evidence.

We are pleased to see that the model will take into account pipework, rather than using a standardised assumption. This will improve the accuracy of the model, as factors such as insulation levels can have a significant impact on heat losses from pipework.

However, the methodology does not seem to take into account the location of the pipework which could influence the calculation. It is important to distinguish between sections of pipework that are in the thermal envelope and those that are outside of it (in the roofwork, for instance) because heat loss from pipework in the thermal envelope could contribute to space heating, thereby skewing calculations.

What are your views on the methodological approach for calculating heat losses from hot water cylinders? Please provide your reasoning and any supporting evidence.

We agree with this approach.

What are your views on future features development for the Home Energy Model? Please make suggestions, explaining your reasoning.

We welcome the Government’s commitment to develop future features in the open. Given that there are key elements of the model which are yet to be finalised and may require further development, it is important that industry is properly consulted throughout its ongoing development, so that businesses can give their views and inform the development of aspects like future features.

The freedom to interact with the open-source code without too many restrictions will be important for software designers. This will allow them to build user interfaces and develop different end uses for the model without a prohibitive cost of entry.

What are your views on the inter-model validation work that has been carried out (i.e. comparison against SAP 10.2 and validation against PHPP and ESP-r)? Please provide your reasoning and any supporting evidence.

We agree with work carried out to benchmark against other models. This approach is sensible and takes account of the most relevant models. It is likely that the introduction of the HEM will shift the goalposts compared to SAP, most likely resulting in lower SAP scores and requiring higher standards of energy efficiency for compliance with building regulations. This is generally positive as it supports the transition towards more energy efficient, ‘Net Zero Carbon ready’ buildings. However, it is important that this aspect of the HEM’s implementation is carefully managed in a way that does not have a detrimental effect on residents, retrofit businesses, and others in the sector.

The findings of the inter-model validation seem to be generally positive. It is critical that these learnings, particularly the areas for improvement identified, are fully addressed in the next stage of the HEM’s development.

What are your views on the validation work that has been carried out against real-world case studies (i.e. IEA Annex 58, Camden Passivhaus, and Marmalade Lane)? Please provide your reasoning and any supporting evidence.

The validation work against real-world case studies is encouraging. It suggests a fairly high level of accuracy within the HEM when compared to real-world performance data. The Marmalade Lane case study findings show that the HEM was consistently more closely aligned with measured data than SAP 10.2, which is positive. This shows that the HEM is significantly more accurate than SAP in practice, and its introduction should help to close the performance gap between predicted and monitored energy use, which is one of the model’s primary aims.

What examples of real-world case studies, or other data, do you suggest be used to further validate the Home Energy Model? Please provide further information.

Contractors and software developers will run their own modelling using the open-source code. It is important that government carefully considers any feedback or issues that arise from independent modelling conducted by industry. It will also be important to gather more data on how residents’ behaviour affects the HEM’s modelling, as this is not explored in detail by the real-world case studies.

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Call for Evidence: Decarbonising home heating – National Insulation Association response

Decarbonising home heating – Committees – UK Parliament

Closing Date: 10 April 2024
Response submitted by: National Insulation Association
For more information, please contact: info@nia-uk.org
About the National Insulation Association The National Insulation Association (NIA) represents the insulation industry in the UK with a member base comprised of installers, system certificate holders, and manufacturers who provide a wide range of insulation solutions for homes and buildings. The NIA and its members are fully committed to maintaining and raising standards within the insulation industry.

Our response to the Call for Evidence

The NIA believe that a fabric first approach to home decarbonisation will provide the best outcomes for residents and best long-term value for money for government. A fabric first approach is the only way to ensure a just transition to net zero homes which does not result in higher energy bills for residents.

Heat pumps are expected to be the main low carbon heating technology for households going forward. In practice, the efficiency of heat pumps is receptive to the fabric efficiency of the home. A fabric first approach which ensures that the home is well-insulated prior to the installation of a heat pump will increase the system’s efficiency and reduce its running costs. Higher levels of insulation should also allow a smaller, cheaper heat pump to be installed that will have lower operating costs. Hence, a fabric first approach to decarbonisation is crucial to protect residents from overly high running costs and ensure that the switch to heat pumps is as affordable as possible for residents.

Since electricity is currently four times more expensive than gas per kWh1, there is a significant risk that, without energy demand reduction measures like insulation, households will be subject to higher energy bills when moving from a gas boiler to an electrified low carbon heating system. With an estimated 6 million households in fuel poverty, according to National Energy Action2, and 41% of all energy bill payers struggling to afford payments3, it is absolutely critical that the transition to decarbonised home heating does not result in higher energy prices for residents. Electricity prices are expected to remain well above pre-crisis levels for the rest of the decade4, therefore a sustainable long-term solution which reduces energy demand is needed in order to make the switch to electrified heating affordable for residents.

In the context of the ongoing energy crisis, the primary concern of the Government must be to make sure that residents are protected from higher energy prices. A fabric first approach to home decarbonisation is the best way to guarantee this in the long-term, as insulation measures reduce energy demand and bills for residents. This approach led to 145,000 households being lifted out of fuel poverty by energy efficiency measures between 2021 and 20225. Increased investment in energy efficiency measures will lift even more households out of fuel poverty in future and ensure that the transition to net zero homes is as affordable as possible for residents. This will make sure that the most vulnerable residents are protected throughout the transition to net zero. As the National Audit Office report points out, the Government has a legal commitment to both reduce emissions and meet its statutory fuel poverty targets6. By taking a fabric first approach to home decarbonisation, the Government can meet both of these legal obligations.

Short term investment in insulation measures not only delivers much-needed financial benefits to residents, it can also save the Government money in the long-term. It is expected that the decarbonisation of homes will be dominated by electrified low carbon technologies, meaning a vast expansion of the electricity network will be required to facilitate the roll out of electrified heating to the majority of homes. There is an enormous capital cost associated with developing more renewable generation capacity and expanding the electricity network to meet this increased demand. According to Ofgem and the Government, £170 billion – £210 billion will need to be invested in the grid by 2050 to achieve our net zero targets7. Therefore, demand reduction measures like insulation are vitally important to ensure that our homes use as little energy as possible to run. Investment in insulation in the short term could save the Government and taxpayers billions in the long run by reducing the extent to which we will need to expand the electricity network and build additional renewable energy capacity.

Insulation upgrades in the short term will also future-proof government and households against future energy crises. With a properly insulated housing stock, the Government will not need to spend billions on subsidising household energy bills in the event of future energy price shocks. For instance, in 2013, the Government decided to cut support for home insulation, which saw installation rates fall by around 90%8. Had the Government maintained 2013 levels of support for home insulation, this could have saved taxpayers £18 billion over the course of the Energy Price Guarantee, according to analysis conducted by the Energy & Climate Intelligence Unit9. Energy prices are set to remain high for the foreseeable future10, therefore, without increased investment in insulation, it is possible that the government may have to step in again with a very expensive support package should prices rise to unaffordable levels again. A fabric first approach to home decarbonisation would avoid this costly outcome and deliver value for money for government in the long term. Insulation measures offer a more cost-effective and permanent solution to high energy bills than nationwide energy bill support schemes. In this way, increased support for insulation now has the potential to save government and residents a significant amount of money in the future.

In addition to the significant financial savings it provides, insulation also has substantial health benefits for residents and wider society. Living in cold, damp homes can increase the risk of a number of illnesses, such as strokes, heart attacks, and respiratory diseases11. For instance, poorly insulated and ventilated homes can double the risk of children developing asthma12. Unfortunately, many homes are in this poor state, with 1 in 5 children in the UK currently exposed to damp and mould at home13. This highlights the urgent need to improve insulation and ventilation across our housing stock, thus helping to eliminate the scourge of damp and mould from homes along with the associated health issues they bring for residents which, as we have seen with the tragic case of Awaab Ishak, can be fatal(14)

The direct personal health benefits delivered by a fabric first approach to decarbonisation are also translated into wider public health and economic benefits to society. According to the Local Government Association, the NHS spends an estimated £2.5 billion per year on treating illnesses linked to cold, damp and unsafe homes15. This represents a significant burden on a health service which is already under significant funding pressures. A fabric first approach to home decarbonisation will create warmer, healthier homes and alleviate pressure on the NHS. Findings from the Energy Systems Catapult’s Warm Homes Prescription project found that enabling residents to live in warm, well-insulated homes reduced pressure on NHS services, with fewer hospital and GP appointments booked by those who had taken part in the trial16. The preventive health benefits it delivers makes insulation an excellent value for money investment for Government and taxpayers – investing £1 in retrofit is estimated to save £0.42 in direct health costs(17). Most importantly, a fabric first approach to decarbonisation will improve the personal health and wellbeing of residents, and enable people up and down the country to live in warmer, healthier and decarbonised homes.

Robust quality assurance is also crucial to ensure to ensure that public money is spent on high-quality installs which deliver the financial and health benefits outlined earlier without any unintended consequences. The Government must continue to ensure that public money is only spent on home decarbonisation projects that are delivered in accordance with the thorough quality assurance frameworks set out in PAS2030/35 and MCS. This is vital to protect consumers from harm. Without stringent quality assurance and consumer protections in place, there is a risk that the Government will open itself up to an increased number of legal complaints and compensation claims regarding sub-standard installs and property damage. As we rapidly increase the quantity of retrofit measures delivered over the coming years, it is imperative that we do not lose sight of the importance of quality. The race to net zero cannot become a race to the bottom in terms of quality standards. Any dilution in quality standards risks fatally undermining the net zero transition and irrevocably damaging consumer confidence in the home decarbonisation industry. Effective quality assurance is important to ensure that home decarbonisation measures deliver quality and value for money for government and residents.

Delivering home decarbonisation at scale without compromising on quality will require a significant increase in the size and skill level of the retrofit workforce. This represents a significant challenge, but also a huge opportunity. With sufficient targeted investment in retrofit skills and training, the Government has the opportunity to create thousands of high-quality, sustainable jobs in local communities across the UK. Based on the Climate Change Committee’s (CCC) projections, 120,000 to 230,000 jobs could be created across the UK construction sector in order to retrofit and insulate the UK housing stock – an 11% increase relative to the current size of the sector18. Importantly, these are also high-quality, skilled trades that pay well. According to Indeed, the average salary for an insulation worker in the UK is £37,17819 – above the national average. Most jobs in the insulation sector do not require a Level 6 qualification (undergraduate degree or equivalent), so employment in this sector will help to level up communities by providing high-skilled and well-paid technical employment for school leavers without a degree.

In addition, most energy efficiency work tends to be localised; therefore, installations will likely be carried out by local installers and businesses, thus ensuring that employment and growth opportunities remain within the local area where they are needed. Which’s recent Priority Places for Insulation Index report shows that many of the places most in need of future insulation upgrades are in deprived areas, for example former coalfields or coastal communities in the north of England20. As such, investment in insulation has the potential to support the Government’s levelling up mission by directing investment and jobs to areas that need it most. In this way, spending on insulation and wider retrofit skills represents a cost-effective investment for government because it creates well-paid, high-quality and sustainable jobs in local areas.

Despite the clear long-term benefits of insulation measures, we recognise that the upfront investment required can be costly for government. To mitigate this, we would like to see the Government provide more support for the development of innovative green finance mechanisms, which will make sure that home decarbonisation policies are cost-effective for government and taxpayers. The CCC estimates that retrofitting all of the UK’s housing stock will cost £250 billion by 205021. It is not reasonable or realistic to expect that government will provide fully funded grants to cover this cost. Neither can most households, many of whom have very limited savings22, be expected to fund the full upfront cost of retrofit without some form of support. Therefore, innovative green financing solutions which effectively mobilise private investment into the retrofit market and spread out the upfront cost of retrofit will be needed to ensure a net zero transition that is cost-effective for government. The Green Home Finance Accelerator represents a welcome start in this area, but the Government urgently needs to work with financial institutions and private investors to develop a range of effective green finance solutions that can be rolled out across the country. This is critical to create long-term, organic consumer demand for decarbonisation measures which is not reliant on expensive government subsidies.

In conclusion, a fabric first approach to decarbonising our homes represents the most effective way to fairly distribute the costs of the net zero transition. Short term investment in insulation will provide a number of longer term savings: reducing the cost of expanding the electricity network, avoiding the need for expensive energy bill support packages during future energy crises and providing significant public health savings, thereby reducing pressure on the NHS. Most importantly, a fabric first approach will enable residents to benefit from clean and affordable heating, along with improved health and comfort. Insulation is vital to ensure a just transition to net zero homes which protects the most vulnerable households in society.

1 Ofgem (2024). Energy price cap. Available here.
2 National Energy Action (2024). What is fuel poverty? Available here.
3 Office for National Statistics (2024). Cost of living insights: Energy. Available here.
4 Jillian Ambrose (2023). ‘Higher energy bills forecast for UK households next year’, The Guardian. Available here.
5 Department for Energy Security and Net Zero (2022). Fuel poverty factsheet: England, 2022. Available here.
6 National Audit Office (2024). Decarbonising home heating. Available here.
7 Regen (2023). Building a GB electricity network for net zero. Available here.
8 Rt Hon Chris Skidmore MP (2022). Mission Zero: Independent Review of Net Zero. Available here.
9 Energy & Climate Intelligence Unit (2022). Taxpayers facing £18 billion bill for failure to insulate UK homes. Available here.
10 Jillian Ambrose (2023). ‘Higher energy bills forecast for UK households next year’, The Guardian. Available here.

Click here to view the full document. 

The Home Energy Model: Making the Standard Assessment Procedure fit for a net zero future

The Home Energy Model (publishing.service.gov.uk)

Closing Date: 27 March 2024
Response submitted by: National Insulation Association
For more information, please contact: info@nia-uk.org

About the National Insulation Association
The National Insulation Association (NIA) represents the insulation industry in the UK with a member base comprised of installers, system certificate holders, and manufacturers who provide a wide range of insulation solutions for homes and buildings. The NIA and its members are fully committed to maintaining and raising standards within the insulation industry.

What are your views on the choice of name for the new model? Please provide your reasoning and any supporting evidence.

We are satisfied with the choice of name.

What are your views on the choice of name for the version of the model which is to be used to demonstrate compliance with the Future Homes Standard? Please provide your reasoning and any supporting evidence.

We are satisfied with the choice of name for the FHS assessment version of the HEM. It makes sense to include specific reference to the FHS, as this makes it clear what the model’s application will be and distinguishes it from the underlying model.

What are your views on using the open-source code as the approved methodology for regulatory uses of the Home Energy Model? Please provide your reasoning and any supporting evidence.

The NIA welcomes the move to publish the open-source code, as this will aid transparency and promote greater understanding of the methodology among relevant stakeholders. It will also give industry experts the chance to scrutinise the code and suggest improvements or raise any potential concerns. This should improve the overall effectiveness of the model.

If the open-source code is used as the approved methodology for regulatory uses of the HEM, we would like to see more clarity and guidance on what the process will be for dealing with errors in the code, in particular around liability and the transfer of risk. If there are errors with the centralised code, it is important that risk and liability is not transferred onto individual software providers who use the code as a basis for producing EPCs and determining compliance with building regulations. It is also important to avoid a situation whereby errors in the code become embedded into law.

It is important that making the open-source code the legal basis for the methodology does not act as a barrier to making necessary changes to the model in a swift manner. It must be possible for the HEM to be constantly improved and refined to improve its effectiveness. There is the potential that a codebase underpinned by regulation will be very slow to change. It is important that this does not act as a barrier to regular updates and improvements to the model. As mentioned earlier, if there are errors in the code, it is vital that these are rectified as soon as possible, without the need for a long, drawn-out regulatory process.

Whilst we agree with publishing the open-source code, it is important that other documents are published alongside it so that people not familiar with Python are still able to understand the methodology behind the model. It is encouraging to see that the Government will be publishing accompanying technical documents to provide further explanation about the model. This will ensure that the methodology is accessible to a wider range of people, thus aligning with the Government’s objective to make the HEM more transparent.

What forms of collaboration would you be interested in for future development of the Home Energy Model codebase? Please provide further details.

There must be a clear process for managing, evaluating and updating the codebase. It is important that industry is involved in this process so that they can shape the future development of the codebase.

What are your views on our assessment of issues with the current SAP delivery model? Please provide your reasoning and any supporting evidence.

We agree with the issues outlined with the current delivery model, however it is unclear how the HEM will resolve all of these, in particular the inertia of the SAP methodology. If the codebase is embedded in regulation, this could complicate and slow down the process of making changes to the methodology. Introducing a centralised, cloud-based version of the code has the potential to enable quicker updates to the methodology. However, it is not entirely clear how this would operate in practice and what the relationship would be with accompanying regulations.

Lack of accountability is a key issue, however it is still unclear from the consultation proposals where the balance of accountability will lie with the HEM. We would welcome clarity on who will be accountable, whether this be the Government, BRE, or independent software providers. If the Government proceeds with a centralised, cloud-based version of the HEM, this could simplify the issue of accountability.

At the moment, different software providers all have differing versions of SAP which can cause inconsistencies in results, although these tend to be small. Having a centralised, standardised code should help to minimise these inconsistencies in results. It should also help to clarify the accountability of different parties by providing one consistent version of the ‘truth’.

What are your views on the concept of a centralised, cloud-based version of the Home Energy Model, to be used for regulatory purposes? Please provide your reasoning and any supporting evidence.

We agree with the concept of a centralised, cloud-based version of the HEM. Currently, different software providers have differing versions of SAP which can lead to inconsistencies in results.

Centralising and standardising the model will help to increase accuracy and minimise these inconsistencies. The ability to make quick updates to the central platform is key.

It can be unclear where the balance of accountability lies with the current version of SAP, whereby different software providers implement differing versions of the methodology independently. Having a centralised, standardised model will help to clarify where accountability lies and transfer risk away from software providers. It is important that it is clear which body is ultimately responsible for the HEM (whether this be BRE or the Government).

The provider of the centralised model (BRE for example) will need to understand and put in place appropriate support arrangements to allow independent software providers to easily build user interfaces around the central platform.

What are your views on revising the database of product characteristics (currently the “PCDB”) for the Home Energy Model? Please provide your reasoning and any supporting evidence.

We agree with the intention to revise the database of product characteristics for the Home Energy Model. It is important that the PCDB is based on accurate and up-to-date data, and includes the most effective technologies currently on the market.

What changes would you recommend to the PCDB data collection procedures? Please provide your reasoning and any supporting evidence.

It is costly for manufacturers to get their products listed in the PCDB. This prohibitive cost means that many products are not listed on the database because it isn’t worth the effort and cost for manufacturers to apply for their products to be listed. The process should be streamlined and made more cost-effective for manufacturers, as the cost of getting products listed is a significant barrier for many.

What are your views on our assessment of issues with the way SAP currently recognises new technologies (currently the “Appendix Q process”)? Please provide your reasoning and any supporting evidence.

We agree with the issues identified around the Appendix Q process. In general, the process is too costly and time-consuming which can act as a barrier for new innovative products being recognised via SAP. The HEM must make it easier for innovative new products to become recognised.

What are your views on the principles for how the Home Energy Model will recognise new technologies once it is in use? Please provide your reasoning and any supporting evidence.

We support the principles set out in the consultation for the how the HEM will recognise new technologies. However, more detail is needed on how the process will work in practice. The reformed Appendix Q process should focus on reducing the cost burden and length of time that it takes for innovative technologies to gain recognition, as this can prove a significant barrier to new innovations entering the market and becoming commercially viable. Ultimately, the HEM needs to enable innovation rather than hinder it.

The opportunity for continuous evaluation should enable regular “live” updates to the HEM which may make it easier and quicker for new, innovative technologies that come onto the market to be recognised by the HEM. Greater integration with other innovation routes such as ECO4 is welcome to avoid the need for companies to duplicate unnecessarily a process which can be costly and time-consuming. More detail is required on how this integration will work in practice.

The ability of innovative technologies to become recognised within SAP also depends on the underlying measurement standard. If the underlying standard is not broad enough to cover innovative technologies, then it is difficult for them to be introduced.

What are your suggestions for other wrappers that could be developed for the Home Energy Model in future? Please provide your reasoning and any supporting evidence.

The proposals identify the main wrappers that should be included within the HEM, excluding the very important EPC wrapper which will be consulted on later this year. In general, we welcome the use of wrappers, as they should improve on the SAP process, however, the HEM’s modelling will only be as accurate as the data inputted into it, therefore it is important to choose the most suitable wrappers to achieve more accurate and reliable outputs.

The effectiveness of wrappers depends on how straightforward it is to interact with the core engine and what controls will be on it. At the moment, it is unclear how open the interface will be and how easy it will be to implement new wrappers. If it Is easy to add new wrappers and build software interfaces, then the wrapper system has the potential to be a lot more efficient than the current system, which can make producing an EPC quite a time-consuming and laborious process. If the wrapper process is efficient and accessible, it should be possible to quickly produce an output wrapper, whereas in SAP it can take hours to manually write up a report.

What are your views on the increased time resolution offered by the Home Energy Model? Please provide your reasoning and any supporting evidence.

The NIA welcomes the increased time resolution offered by the HEM. This will increase the accuracy of the HEM compared to SAP and bring a range of other benefits including:

• More accurate modelling of heat pump performance and importantly the interaction with other building elements within the whole building system.
• Better alignment of the HEM with improvements in real-time monitoring and evaluation of building Enabling these improvements to be reflected within the model will enhance its accuracy and help to close the performance gap.
• More recognition of the benefits of smart technologies and the importance of energy

Despite the clear benefits of increasing the time resolution, we are concerned by the longer runtime of the HEM which has been identified as an issue by the Government. Industry urgently needs more detail and clarity on exactly how long the expected runtime of the HEM will be. It is very important that the HEM still has a reasonable runtime that does not make the model impractical to run. For instance, a runtime of 5 minutes, although not ideal, would most likely still be workable for industry. By contrast, a runtime of 15 minutes or more would represent a substantial challenge for SAP users and would significantly reduce the effectiveness of the HEM in practice.

What are your views on the choice of BS EN ISO 52016-1:2017 (in its half-hourly form) as the basis for the Home Energy Model? Please provide your reasoning and any supporting evidence.

The move to BS EN ISO 52016-1:2017 which is a recognised industry standard seems reasonable. There are clear benefits associated with moving to a standard that supports the HEM’s half- hourly simulation.

What are your views on the ability of the Home Energy Model to model energy flexibility and smart technologies? Please provide your reasoning and any supporting evidence.

The half-hourly time resolutions of the HEM gives it the potential to model energy flexibility much more accurately than SAP.

The usefulness of the HEM for modelling energy flexibility depends on the range of applications it is used for. The existing SAP methodology focuses on the building as an asset and ignores the occupants and their energy consumption habits in favour of standardised assumptions. The HEM’s potential for modelling energy flexibility is unlikely to be relevant when assessing a building’s compliance with building regulations for example, as this is solely based on the building’s performance as an asset. Energy flexibility is dependent on energy suppliers and occupants which is largely out of the control of developers and retrofit contractors.

It is clearly useful to have a model that can take into account energy flexibility and the use of smart technologies, particularly as these start to become more commonplace in homes. It is important to have a model that is responsive to changing patterns of energy consumption and the increased energy flexibility that smart technologies can bring for residents. However more detail is required from government on how it intends to use the HEM’s potential capabilities around energy flexibility and smart technologies. For instance, this could be used to model custom energy demand.

What are your views on the methodological approach for calculating space heating and cooling demand? Please provide your reasoning and any supporting evidence.

We support the methodological approach for calculating space heating and cooling demand. The new approach, as well as the use of more detailed inputs, will model the space heating demand of buildings more accurately than SAP. It is possible that it will lead to a higher space heating demand calculation than SAP, which will incentivise greater reductions in energy demand through increased fabric efficiency.

What are your views on the methodological approach for calculating fabric heat loss? Please provide your reasoning and any supporting evidence.

We agree with this approach.

What are your views on the methodological approach for calculating thermal bridges? Please provide your reasoning and any supporting evidence.

We agree with this approach.

What are your comments on the methodological approach for calculating infiltration and/or controlled ventilation? Please provide your reasoning and any supporting evidence.

We agree with the methodological approach for calculating infiltration. This should increase accuracy because it takes into account more factors and uses wind speeds updated on an hourly basis, making it much more receptive to changes in weather conditions. The omission of other contributing factors such as wind direction and “stack effect” from the HEM are unlikely to have a significant effect on the accuracy of the modelling. However, we would support their future inclusion, along with any other updates which increase the granularity and accuracy of the modelling. We also support replacing the fixed minimum dwelling ventilation rate with a wrapper input value as this will make the modelling more dwelling-specific.

What are your views on the methodological approach for calculating thermal mass? Please provide your reasoning and any supporting evidence.

We welcome the approach to include the entire building envelope within thermal mass calculations. This should produce a more accurate calculation than SAP 10.2 which only takes part of the construction envelope into account. Including warm up and cool down rates will also increase accuracy compared to the current approach based on a one-off, instantaneous value which doesn’t reflect how buildings warm up and cool down in practice.

While we support the desire to be as accurate and dwelling-specific as possible, we do not agree with the proposal to include the thermal mass of furniture in thermal mass calculations. Many properties, especially in the non-domestic sector, are unfurnished. It is not clear how the current approach would account for unfurnished properties. Furthermore, it doesn’t make sense for furniture to be taken into account when determining a building’s SAP rating or compliance with building regulations. This is often out of the control of developers and may depend on the personal choices of residents. We do not think that the negligible increase in accuracy that including furniture in thermal mass calculations will bring outweighs the issues that this approach may create.

What are your views on the methodological approach for calculating solar gains and solar absorption? Please provide your reasoning and any supporting evidence.

We support the approach for calculating solar gains and solar absorption, as it should provide more accurate results than the current version of SAP.

What are your views on the methodological approach for calculating heat losses from Domestic Hot Water pipework? Please provide your reasoning and any supporting evidence.

We are pleased to see that the model will take into account pipework, rather than using a standardised assumption. This will improve the accuracy of the model, as factors such as insulation levels can have a significant impact on heat losses from pipework.

However, the methodology does not seem to take into account the location of the pipework which could influence the calculation. It is important to distinguish between sections of pipework that are in the thermal envelope and those that are outside of it (in the roofwork, for instance) because heat loss from pipework in the thermal envelope could contribute to space heating, thereby skewing calculations.

What are your views on the methodological approach for calculating heat losses from hot water cylinders? Please provide your reasoning and any supporting evidence.

We agree with this approach.

What are your views on future features development for the Home Energy Model? Please make suggestions, explaining your reasoning.

We welcome the Government’s commitment to develop future features in the open. Given that there are key elements of the model which are yet to be finalised and may require further development, it is important that industry is properly consulted throughout its ongoing development, so that businesses can give their views and inform the development of aspects like future features.

The freedom to interact with the open-source code without too many restrictions will be important for software designers. This will allow them to build user interfaces and develop different end uses for the model without a prohibitive cost of entry.

What are your views on the inter-model validation work that has been carried out (i.e. comparison against SAP 10.2 and validation against PHPP and ESP-r)? Please provide your reasoning and any supporting evidence.

We agree with work carried out to benchmark against other models. This approach is sensible and takes account of the most relevant models. It is likely that the introduction of the HEM will shift the goalposts compared to SAP, most likely resulting in lower SAP scores and requiring higher standards of energy efficiency for compliance with building regulations. This is generally positive as it supports the transition towards more energy efficient, ‘Net Zero Carbon ready’ buildings. However, it is important that this aspect of the HEM’s implementation is carefully managed in a way that does not have a detrimental effect on residents, retrofit businesses, and others in the sector.

The findings of the inter-model validation seem to be generally positive. It is critical that these learnings, particularly the areas for improvement identified, are fully addressed in the next stage of the HEM’s development.

What are your views on the validation work that has been carried out against real- world case studies (i.e. IEA Annex 58, Camden Passivhaus, and Marmalade Lane)? Please provide your reasoning and any supporting evidence.

The validation work against real-world case studies is encouraging. It suggests a fairly high level of accuracy within the HEM when compared to real-world performance data. The Marmalade Lane case study findings show that the HEM was consistently more closely aligned with measured data than SAP 10.2, which is positive. This shows that the HEM is significantly more accurate than SAP in practice, and its introduction should help to close the performance gap between predicted and monitored energy use, which is one of the model’s primary aims.

What examples of real-world case studies, or other data, do you suggest be used to further validate the Home Energy Model? Please provide further information.

Contractors and software developers will run their own modelling using the open-source code. It is important that government carefully considers any feedback or issues that arise from independent modelling conducted by industry. It will also be important to gather more data on how residents’ behaviour affects the HEM’s modelling, as this is not explored in detail by the real- world case studies.

Click here to view the full response. 

The Future Homes and Buildings Standards: 2023 consultation

The Future Homes and Buildings Standards: 2023 consultation – GOV.UK (www.gov.uk)

Closing Date: 6 March 2024
Response submitted by: National Insulation Association
For more information, please contact: info@nia-uk.org

About the National Insulation Association
The National Insulation Association (NIA) represents the insulation industry in the UK with a member base comprised of installers, system certificate holders, and manufacturers who provide a wide range of insulation solutions for homes and buildings. The NIA and its members are fully committed to maintaining and raising standards within the insulation industry.

Which option for the dwelling notional buildings (for dwellings not connected to heat networks) set out in The Future Homes Standard 2025: dwelling notional buildings for consultation do you prefer?

1. Option 1 (higher carbon and bill savings, higher capital cost)

Option 1 is our preferred option because Option 2, as the Government’s own modelling shows, would leave residents exposed to higher annual energy bills than the 2021 uplift to Part L. The FHS should not under any circumstances lead to higher energy bills for residents than existing new build standards. This would be a completely unacceptable outcome. Therefore, we do not consider Option 2 to be a viable option. Furthermore, as outlined by a cross-industry letter sent to the Secretary of State for Levelling Up, Housing and Communities, there is a risk that Option 2 would contravene the Government’s public sector equality duty by introducing a standard which ‘would unduly affect those on lower incomes’.1

While we support Option 1 over Option 2, it is worth noting that these are the two least ambitious options of the five considered by the Future Homes Hub in their ‘Ready for Net Zero’

Report.2 For instance, home heating demand in the Report’s Contender Specification 4 is just % of that in Option 1 of the FHS, meaning that the options under consideration in the FHS will incur significantly higher bills and carbon emissions. The NIA believe that the U-values outlined in the Option 1 specification need to be tightened further for a number of reasons.

• To protect residents from high energy Heating systems installed under the FHS are expected to be dominated by electrified options like heat pumps. The high electricity to gas price ratio (3.86 to 1 as of the January 2024 price cap level)3means that without significant energy demand reduction measures, residents with electrified heating will be exposed to high energy bills. As such, insulation measures which lower energy demand are especially important with electrified heating options. More ambitious insulation requirements will mean that households living in new builds with electric heating are protected from the risk of high energy bills. This is particularly important given the current cost-of-living and energy crises, with electricity prices expected to remain well above pre-crisis levels for the rest of the decade.4 Therefore, the NIA would like to see stricter U-values to protect vulnerable consumers from high electricity prices.
• To increase the efficiency and reduce the running costs of heat The efficiency of heat pumps is receptive to the fabric efficiency of the home. Introducing more ambitious U-values will increase the efficiency of heat pumps and reduce the cost they incur to run. Higher insulation standards should allow a smaller, cheaper heat pump to be installed that will have lower operating costs for residents. Real-world monitoring and testing is key to find out how the fabric works in practice, enabling more accurately sized heating systems to be installed. Correctly sized heat pumps will operate at a higher efficiency than incorrectly sized systems. Ambitious fabric standards bolstered by effective monitoring and testing will result in more efficient and cheaper-to-run heating systems.
• To reduce the cost of electricity network expansion. If the majority of new (and ultimately existing) homes are to replace gas with electric heating, a huge expansion of the electricity grid will be required. There is a huge capital cost associated with building more renewable generation capacity and expanding the electricity network. According to Ofgem and the Government, £170bn – £210bn will need to be invested in the grid by 2050 to achieve our net zero targets.5Therefore, it is imperative that we build homes which use as little electricity to run as possible because the cheapest energy is the energy we don’t use. High insulation standards which reduce the energy demand of new homes will reduce the scale by which the electricity network and additional renewable capacity will need to be expanded by, thus saving billions in capital costs for residents and government. It will also increase energy security by reducing our demand for energy imports from overseas.

¹ Good Homes Alliance (2024). Future Homes Standard Consultation Response. Available at: Future Home Standard response – Good Homes Alliance
² Future Homes Hub (2023). Ready for Zero: Evidence to inform the 2025 Future Homes Standard. Available at: Ready for Zero – Evidence to inform the 2025 Future Homes Standard -Task Group Report FINAL- 280223- MID RES.pdf (cdn-website.com)
³ Ofgem (2024). Energy price cap. Available at: Energy price cap | Ofgem
⁴ Jillian Ambrose (2023). ‘Higher energy bills forecast for UK households next year’, The Guardian. Available at: Higher energy bills forecast for UK households next year | Energy bills | The Guardian
⁵ Regen. Building a GB electricity network ready for net zero. Available at: Building a GB electricity network for net zero (regen.co.uk)

What are your priorities for the new specification? (select all that apply)

Our priorities for the new specification are:

• Lower energy Lower energy bills are a vital consideration, particularly in the context of the ongoing cost of living and energy crises. The FHS should make every effort to reduce energy bills for residents. For this reason, we support Option 1 which would result in significantly lower energy bills compared to current new build standards. However, as outlined in our response to Question 7, we believe that Option 1 should be more ambitious in terms of insulation. Setting higher insulation standards, in conjunction with the solar PV provisions in Option 1, would ensure that energy bills are as affordable as possible for residents.
• Carbon savings. Higher insulation standards would also have the added advantage of additional carbon savings. The generation emissions factor for grid electricity in the UK is still around 0.2 kg CO2e per kWh.⁶This means that every unit of electricity consumed carries with it associated CO2 Given that the Government does not expect the UK’s electricity grid to be fully decarbonised until 20357, it is imperative that new homes consume as little electricity as possible. The most effective way to do this is by setting higher minimum insulation standards within the FHS.
• Protecting residents’ health. Option 1 sets higher ventilation standards, which are important to prevent the risk of damp and mould, and the potential health issues associated with it. However, we think that Option 1 could also be more ambitious when it comes to ventilation. For instance, it could require mechanical ventilation with heat recovery (MVHR). This would improve air quality, and reduce the risk of condensation and mould, while also conserving heat Strict ventilation minimum requirements are important to go along with increased insulation and airtightness requirements. A combination of high insulation and ventilation standards are the best way to protect residents’ health.
• Reducing pressure on the electricity grid and the capital cost needed to upgrade it. As mentioned in Question 7, the electrification of heat will necessitate a huge expansion of the electricity grid, which comes with a large capital cost associated with building more renewable generation capacity and expanding the electricity network. Therefore, high standards around insulation and solar PV are important to reduce the electricity that new homes require from the grid. This will increase our energy security and save billions in capital costs for government and taxpayers.

⁶ ITPEnergised (2023). New UK grid emissions factors 2023. Available at: New UK Grid Emissions Factors 2023 – ITPEnergised
⁷ Carbon Brief (2023). CCC: Here’s how the UK can get reliable zero-carbon electricity by 2035. Available at: CCC: Here’s how the UK can get reliable zero-carbon electricity by 2035 – Carbon Brief

Which option for the dwelling notional buildings for dwellings connected to heat networks set out in The Future Homes Standard 2025: dwelling notional buildings for consultation do you prefer?

a. Option 1 (higher carbon and bill savings, higher capital cost)

Which option do you prefer for the proposed non-domestic notional buildings set out in the NCM modelling guide?

a. Option 1

What are your priorities for the new specification?

Our priorities for the new specification are:

• Lower energy bills. For commercial buildings, lower bills are important to enable businesses to reduce their overhead costs, which continue to be a significant burden for many during the energy crisis. A survey conducted by PwC in 2023 found that 77% of business respondents had to raise their prices over the past two years as a result of energy-related expenditures8, thus driving inflation across the economy. Moreover, reducing the percentage of their budget spent on overhead costs will enable businesses to invest more in productive activities, such as hiring and training staff and creating economic growth. For this reason, we support Option 1 which would result in significantly lower energy bills compared to current standards. However, we believe that Option 1 should be more ambitious in terms of insulation standards, as set out in our responses to Questions 7 and 8.
• Carbon savings. Our preferred choice is Option 1 as it would deliver higher carbon savings. However, we would like to see higher insulation standards, as mentioned in our responses to Questions 7 and 8.
• Reducing pressure on the electricity grid and the capital cost needed to upgrade As mentioned in Questions 7 and 8, high standards for insulation and solar PV are important to reduce the electricity that new buildings require from the grid. This will increase our energy security and save billions in capital costs for government and taxpayers.

⁸ Sidhi Mittal (2024). ‘British businesses struggling to find right solutions to cut energy costs, survey finds’, Edie. Available at: UK Businesses Grapple with Rising Energy Costs According to PwC Survey (edie.net)

Do you agree that the metrics suggested above (TER, TPER and FEE) be used to set performance requirements for the Future Homes and Buildings Standards?

a) Yes, and I want to provide views on the suitability of these metrics and/or their alternatives.

We agree with the three metrics suggested, however we would like to see an additional metric added to take into account the building’s real-world fabric performance. This additional metric would be based on the results of mandatory post occupancy testing, which we have outlined our support for in Question 40. This Actual/Real Fabric Energy Efficiency metric could be compared to the DFEE to test how the property’s real-world fabric performance compares to its target DFEE rate. Including this as an additional metric would help to close the performance gap between how homes are designed and built. This would give residents and government confidence that buildings are actually being constructed in practice to the standards stipulated by the FHS and Building Regulations.

Mandatory post-occupancy testing, backed up by a metric that measures real-world fabric performance, would reward good performance from housebuilders and retrofit businesses, and generally drive up quality standards across the housing sector.

Do you agree with the proposed changes to minimum building services efficiencies and controls set out in Section 6 of draft Approved Document L, Volume 1: Dwellings?

Yes.

Do you agree with the proposed changes to Section 4 of draft Approved Document L, Volume 1: Dwellings, designed to limit heat loss from low carbon heating systems?

Yes.

Do you agree with the proposed guidance on the insulation standard for building heat distribution systems in Approved Document L, Volume 2: Buildings other than dwellings?

Yes.

Do you agree that the current guidance for buildings with low energy demand which are not exempt from the Building Regulations, as described in Approved Document L, Volume 2: Buildings other than dwellings should be retained without amendment?

Yes.

Should we set whole-building standards for dwellings created through a material change of use?

Yes.

Should the proposed new MCU standard apply to the same types of conversion as are already listed in Approved Document L, Volume 1: Dwellings?

No, standards should also apply to non-dwelling accommodation e.g., student or patient accommodation, care homes, and hotels. In many of the buildings classified as non-dwelling accommodation, residents live there on a semi-permanent basis. We do not believe that buildings which are used as a main place of residence for a significant proportion of the year, such as care homes, patient accommodation, and student accommodation, should be subject to weaker energy efficiency requirements than residential conversions.

Care homes and patient accommodation are used to house some of the most vulnerable people in society, who may be more susceptible to living in cold, damp and inefficient homes. Thus, it is crucial that these types of non-dwelling accommodation are subject to high MCU energy efficiency requirements.

Should different categories of MCU buildings be subject to different requirements?

Yes.

Which factors should be taken into account when defining building categories? (check all those that apply)

The following factors should be taken into account when defining building categories:

• height of the building, e., low versus mid- to high-rise buildings
• floor area of the building
• whether the conversion is a part- or whole-building conversion

Do you agree with the illustrative energy efficiency requirements and proposed notional building specifications for MCU buildings?

Yes.

If you answered no to the previous question, please provide additional information to support your view. Select all that apply. The requirements are:

Not applicable.

Do you agree with using the metrics of primary energy rate, emission rate and fabric energy efficiency rate, if we move to whole dwelling standards for MCU buildings?

Yes, and I want to provide additional suggestions or information to support my view.

As outlined in our response to Question 12, we would also support the inclusion of a metric that measures real-world fabric performance.

Under what circumstances should building control bodies be allowed to relax an MCU standard?

Building control bodies should be allowed to relax an MCU standard under the following circumstances:

• The technical or practical feasibility of achieving the It is important that buildings subject to an MCU are upgraded to the highest possible standards of energy efficiency. However, in some cases, we accept that it may not be technically or practically feasible to reach the required standards, for example, if there is no space or access to install the required insulation.
• Consideration of historic and traditional dwellings. We also recognise that reaching the required MCU standard might not be possible or practical in some historic and traditional buildings, particularly where listed building or conservation status applies.

Do you have views on how we can ensure any relaxation is applied appropriately and consistently?

As set out in our response to Question 32, we recognise that there are certain circumstances where MCU standards may need to be relaxed for practical purposes. However, it is crucial that any exemptions to the standards are robustly policed and accompanied by clear guidance to make sure that developers are only granted exemptions when there is a genuine barrier preventing adherence to the standards. Wherever practically possible, developers must be required to meet high energy efficiency standards in order to ensure that the benefits of energy efficiency measures for the climate and building occupants are fully realised.

Therefore, the NIA believe that the following should be in place to ensure any relaxation is applied appropriately and consistently:

• Only formal relaxation or dispensation through the local authority should be
• There should be guidance on circumstances where relaxation of the notional standard may be appropriate so that it is clear and unambiguous for developers when they are and are not required to meet MCU standards.

Should a limiting standard be retained for MCU dwellings?

Yes.

Even in dwellings where it is not possible to achieve the MCU whole building standard, there should still be minimum limiting standards for fabric insulation. These minimum standards are important to safeguard occupants from high energy bills.

They are also critical to prevent building defects from occurring. If there are sub-standard levels of insulation and ventilation within MCU dwellings, there will be a significantly increased risk of damp and mould, which poses a serious threat to residents’ health.

If a limiting standard is retained, what should the limiting standard safeguard against?

Limiting standards should be retained and they should safeguard against:

• risk of moisture, damp and mould
• high energy demand and energy bills

Do you agree that a BREL report should be provided to building control bodies if we move to energy modelling to demonstrate compliance with MCU standards?

Yes, and photographic evidence is needed.

Do you agree that consumers buying homes created through a material change of use should be provided with a Home User Guide when they move in?

Yes, and I’d like to provide further information.

We agree that consumers buying MCU homes should be provided with a Home User Guide when they move in. Supporting information and advice is important to make sure consumers operate energy efficiency technologies in a way that maximises their efficiency and effectiveness. This is particularly important when it comes to operating low carbon and smart technologies that they may be unfamiliar with.

Do you agree that homes that have undergone an MCU should be airtightness tested?

Yes, and I’d like to provide further information.

Airtightness testing will help to enforce fabric requirements by ensuring that the building fabric performs in practice as modelled. We would support mandatory airtightness testing for all homes including those that have undergone an MCU. This should be accompanied by increased minimum ventilation standards as a higher level of airtightness without sufficient ventilation can increase the risk of condensation and mould.

Do you think that we should introduce voluntary post occupancy performance testing for new homes?

Yes, and I’d like to provide further information.

Introducing post occupancy performance testing will help to protect consumers from experiencing higher bills and lower comfort levels. It will also build consumer confidence in the benefits of energy efficiency measures and the quality of work being carried out by the industry. However, we would like to see post occupancy performance testing implemented as a mandatory requirement, rather than a voluntary measure. Historically, voluntary options have seen very low uptake, therefore implementing this as a voluntary measure will likely result in only a small uptake in occupancy testing, and create an unfair market.

In addition, this approach creates a risk for housebuilders, as those who engage with post occupancy testing could be penalised for reporting the post occupancy testing results – as without mandated testing, 100% compliance is assumed.

Post occupancy testing ensures that homeowners get maximum benefit and the lowest possible bills from purchasing a new home, by reassuring them that their home achieves the efficiency level promised in the design in practice. Post occupancy testing is also important to ensure that homes have correctly sized heating systems, particularly as incorrectly sized heat pumps will

operate at a lower efficiency than correctly sized ones. Real-world monitoring and testing is crucial to find out how the fabric works in practice. This measurement will enable more accurately sized heating systems to be installed and ensure the house operates as an efficient whole house system. It is crucial that the fabric meets its target design efficiency in practice under real-world occupancy.

Mandatory testing should instead be introduced through sampling a percentage of homes to ensure compliance. For example, occupancy testing could be mandated for 10% of completions. Mandating post occupancy testing and making results publicly available will assist with improving quality and provide evidence for real-world efficiencies to monitor effectiveness and non- compliance with standards. This knowledge would help to improve the overall quality of the industry, alleviating the performance gap and raising consumer confidence. There is likely to be a significant performance gap without mandatory post occupancy testing.

Do you think that the government should introduce a government-endorsed Future Homes Standard brand? And do you agree permission to use a government-endorsed Future Homes Standard brand should only be granted if a developer’s homes perform well when performance tested? Please include any potential risks you foresee in your answer.

Yes, and I want to provide additional suggestions or information.

Implementing a government-endorsed Future Homes Standard brand is a positive way to incentivise housebuilders to engage with post occupancy testing to improve and maintain quality standards.

However, there must be a robust quality assurance process in place to ensure that the brand is credible and trustworthy, or risk damaging consumer confidence in the FHS. The brand should only be awarded to housebuilders that have consistently high-quality outputs, and not simply for those who measure performance. This aligns with leading a ‘race to the top’ on quality within the market. If there is not a robust process in place that only rewards consistently high-quality completions, the brand will not achieve the intended purpose and consumers will have difficulty differentiating between good quality and poor quality homes.

In addition, a Future Homes Standard brand is a good opportunity to introduce a public awareness campaign to improve consumer education about energy efficiency measures and standards. This could help with tackling the performance gap regarding the issue of user behaviour.

Do you agree with the proposed changes to Approved Document F, Volume 1: Dwellings to improve the installation and commissioning of ventilation systems in new and existing homes?

Yes, and I’d like to provide further information

We support the proposed changes, as more rigorous testing should lead to higher quality installations of ventilation systems and reduce the risk of condensation and mould resulting from sub-standard installs.

Nonetheless, we recognise that the increased cost of testing equipment, such as calibrated powered flow hoods, represents a barrier to compliance for some contractors. Therefore, we would urge the Government to provide support for contractors to purchase the necessary equipment. This will increase rates of compliance with the new ventilation rules and lead to higher quality across the insulation and ventilation sector.

Do you agree with the proposal to extend Regulation 42 to the installation of mechanical ventilation in existing homes as well as new homes?

We support increased testing of ventilation systems installed into existing homes. This will ensure that ventilation systems installed into residents’ homes are installed correctly and perform as intended. More extensive testing should reduce the incidence of poor quality installs, which can have damaging consequences for residents.

Do you agree with proposed changes to Approved Document L, Volume 1: Dwellings and Approved Document F, Volume 1: Dwellings to (a) clarify the options for certifying fixed building services installations and (b) set out available enforcement options where work does not meet the required standard?

Yes, and I’d like to provide further information.

We welcome further clarity on the options for certifying fixed building services. It is crucial that robust monitoring and enforcement mechanisms are in place to make sure that work is being carried out to the required standard. To this end, it is clear that building control bodies need more resources in order to properly enforce compliance with Building Regulations. For the Future Homes Standard to achieve its objectives, it is absolutely essential that it is backed up by effective enforcement mechanisms.

Do you have a view on how Home User Guides could be made more useful and accessible for homeowners and occupants, including on the merits of requiring developers to make guides available digitally? Please provide evidence where possible.

Yes, (please provide further details)

Developers should be required to make guides available digitally alongside paper copies. It is important that information is easily accessible for existing and also future residents. It can be very difficult for residents to find out property-specific information when they move into a new home, including details of any historic building works or retrofit works that have been carried out. Making Home User Guides digitally available and searchable via a centralised online database would make it much easier for residents to find out important information and help them to maintain their home more effectively. Many consumers may be unfamiliar with some of the technologies installed in new homes, so Home User Guides available digitally are vital to aid

their understanding of new technologies and how to operate them effectively.

Do you think that local authorities should be required to ensure that information required under Regulations 39, 40, 40A and 40B of the Building Regulations 2010 has been given to the homeowner before issuing a completion certificate?

Yes.

Do you agree that it should be possible for Regulation 26 (CO2 emission rates) to be relaxed or dispensed with if, following an application, the local authority or Building Safety Regulator concludes those standards are unreasonable in the circumstances?

Yes, but we believe that relaxation should only be allowed in exceptional circumstances, if for instance, the required energy efficiency measures cannot be installed safely. Use of this power must be policed and monitored very closely to ensure that it is not being used as a loophole to undercut energy efficiency standards without very good reason.

Do you think that local authorities should be required to submit the applications they receive, the decisions they make and their reasoning if requested?

Yes, and I’d like to provide further justification.

If Regulation 26 is subject to potential relaxation or dispensation, the relaxation process must be monitored very closely. Local authorities should be required to submit records of their decisions and the justifications for making them. This is essential to ensure that relaxation powers are not abused and do not become a convenient loophole by which developers can bypass the Future Homes and Buildings Standard.

Local Authorities’ use of these powers should be monitored closely and subject to enforcement action if necessary. For instance, if certain Local Authorities are found to be granting particularly high numbers of dispensations compared to others, an investigation may be required into whether they are abusing dispensation powers, accompanied by appropriate enforcement action if abuses are found to have been taking place.

Are there any additional safeguards you think should be put in place to ensure consistent and proportionate use of this power?

As noted in our response to Question 63, stringent monitoring and enforcement is critical to ensure consistent and proportionate use of this power.

Do you agree that Part L1 of Schedule 1 should be amended, as above, to require that reasonable provision be made for the conservation of energy and reducing carbon emissions?

Yes.

Do you agree that regulations 25A and 25B will be redundant following the introduction of the Future Homes and Buildings Standards and can be repealed?

Yes.

Do you agree that the Home Energy Model should be adopted as the approved calculation methodology to demonstrate compliance of new homes with the Future Homes Standard?

Yes, and I’d like to provide further information.

We agree with the use of the Home Energy Model (HEM) as the approved methodology to demonstrate compliance with the FHS. A replacement for SAP is long overdue and we welcome the increased accuracy that the HEM will bring.

However, given the tight timelines involved and the fact that the HEM is not yet finalised, there is a risk that it may not be ready for the introduction of the FHS. The Government’s consultation on the HEM makes it clear that the HEM is still undergoing development in multiple areas and lacks detail on certain aspects of the model’s design. The Government must work quickly to ensure that the HEM is fully finalised and any major issues with its design are resolved by the time the FHS is introduced. It is absolutely essential that the introduction of the FHS is not pushed back due to issues or delays with the HEM.

Do you agree with the revised guidance in The Future Homes Standard 2025: dwelling notional buildings for consultation no longer includes the average compliance approach for terraced houses?

Yes.

Do you agree with the proposed approach to determine U-values of windows and doors in new dwellings?

Yes.

Do you agree with the proposal to remove the default y-value for assessing thermal bridges in new dwellings?

Yes.

Which option describing transitional arrangements for the Future Homes and Buildings Standard do you prefer? Please use the space provided to provide further information and/or alternative arrangements.

Option 1

Option 1 provides an adequate transitionary period, whilst ensuring that we continue the momentum towards net zero targets. Furthermore, this option is followed by a separate 12-month transitional period anyway, which should minimise the impact on developers.

Do you agree that the 2010 and 2013 energy efficiency transitional arrangements should be closed down, meaning all new buildings that do not meet the requirements of the 2025 transitional arrangements would need to be built to the Future Homes and Buildings Standards?

Yes.

The NIA agree that the 2010 and 2013 energy efficiency transitional arrangements should be closed so that all new buildings are built to the Future Homes and Buildings Standards. Maintaining previous standards would be incompatible with reaching net zero targets and unfair for consumers who would be burdened with the costs of retrofitting a home built to old, outdated standards. This transition is fairest for the consumer, drives the construction industry to adopt more sustainable practices and aligns with net zero targets. To aid this transition, information, advice and guidance should be in place to support homeowners and housebuilders through the transition.

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