The consultation on amendments to the Standard Assessment Procedure (SAP) and Reduced Data SAP (RdSAP) for the Energy Company Obligation schemes closed on 11 September 20231. The National Insulation Association (NIA), which represents installers, system certificate holders and manufacturers in the insulation industry, has published the response it submitted1.
The proposals would move ECO4 retrofits requiring a full SAP assessment from SAP2012 to SAP10.2, with a six month transition period during which either version could be used1. The NIA agreed with both the change and the transition length, noting that SAP10.2 is already in use across England, Scotland and Wales and that six months matches the completion timeline for ECO4 projects with a district heating element1. The consultation set out three options for evidencing retrofits under RdSAP10.2. The NIA's top preference was Option 2, under which the Building Research Establishment (BRE) would publish a conversion methodology allowing pre-retrofit SAP ratings to be converted from RdSAP2012 to RdSAP10.21. The association said it had no second preference, describing Option 2 as the only viable option1.
"Modelling carried out by an NIA member, based on 5 different property archetypes with differing retrofit scopes, shows that RdSAP10.2 lowers both properties' pre- and post-retrofit scores when compared to RdSAP2012."
The NIA said this fall is particularly significant in projects that include renewables, and that under Option 3 there is a substantial risk that retrofits which would have reached a post-retrofit SAP band of mid to low C would no longer meet the ECO4 Minimum Requirement1. It also raised the interaction with the Minimum Energy Efficiency Standard, warning that private rented properties previously compliant under RdSAP2012 may no longer be compliant under RdSAP10.21. On timing, the NIA said the BRE must publish its conversion methodology well in advance of March 2024, the expected changeover date1. It agreed that three months is sufficient to complete retrofits after RdSAP10.2 is introduced, though it said schemes with large scale projects, such as the Social Housing Decarbonisation Fund, may need longer1.
| Consultation point | NIA position |
|---|---|
| Move ECO4 full SAP assessments to SAP10.2 | Agreed, subject to transition1 |
| Six month transition period | Agreed1 |
| Evidencing options | Option 2 preferred; no second preference1 |
| Three months to complete retrofits | Agreed1 |
| Ofgem scoring methodology unchanged for ECO4 | Agreed1 |
Why it matters for households
The rating method behind a home's Energy Performance Certificate decides whether a property qualifies for supplier-funded insulation and heating measures under the Energy Company Obligation and the Great British Insulation Scheme. If RdSAP10.2 produces lower scores, as the NIA's modelling indicates, some homes that would have passed the eligibility threshold under the old method may not pass under the new one1. That affects whether a household can get work done at reduced or no cost, and it affects private rented properties where a landlord is trying to reach a required band1. The NIA cited Office for National Statistics figures showing 704,000 properties in England are still rated E, F or G, and National Energy Action estimates of 6.6 million households in fuel poverty1. It also stated that the UK has some of the least energy efficient properties in Europe1. For a household, the practical question is whether the measures that improve a home's energy independence, such as insulation and a change of heating system, still count towards the scheme threshold once the scoring changes.
What happens next
The consultation closed on 11 September 20231. The NIA said the government needs to decide on an approach and the BRE needs to publish its conversion methodology as soon as possible so that industry has time to prepare before the expected March 2024 changeover1. No government response to the consultation is reported in the NIA's document1. The consultation process and the ECO4 scheme remain the reference points for how the change would be applied.