Ofgem published the original Great British Insulation Scheme scores matrix on 30 May 20231. The matrix sets out the scores energy companies receive for measures installed under the scheme, and is published as guidance on Ofgem's site1.
The scheme adopts the ECO4 partial project scores framework, so the matrix is identical to the ECO4 partial project score matrix, with the exception of ineligible measure types being removed1. Ofgem directs readers to Chapter 6 of the Great British Insulation Scheme Delivery Guidance for detailed information on how the scores work1.
"The Great British Insulation Scheme scores matrix outlines the scores energy companies receive for measures installed under the scheme."
The page records three versions of the matrix. Version 1 is dated 30 May 2023, the original publication1. Version 2, dated 20 July 2023, added Hybrid Wall Insulation (HWI) measure types1. Version 3, dated 22 April 2025, added scores for Smart Thermostat measures1. A further update applies to Version 3 and is dated 06 August 20251.
| Version | Date | Change |
|---|---|---|
| Version 1 | 30 May 2023 | Original publication of the scores matrix1 |
| Version 2 | 20 July 2023 | Hybrid Wall Insulation (HWI) measure types added1 |
| Version 3 | 22 April 2025 | Scores for Smart Thermostat measures added1 |
| Update to Version 3 | 06 August 2025 | Smart thermostat notification rules tied to the RdSAP version used in the pre-retrofit assessment1 |
On smart thermostats, Ofgem states that whether a product is eligible to be notified as a smart thermostat depends on the version of RdSAP used in the pre-retrofit assessment1. Where that assessment uses RdSAP 10, a product can only be notified as a smart thermostat where it is listed in the SAP 10 PCDB as a smart thermostat, for use with the heat source of the home where it is installed1. Ofgem says the PCDB currently lists smart thermostat products only for condensing gas boilers, non-condensing gas boilers, condensing LPG boilers and non-condensing liquefied petroleum gas (LPG) boilers1.
The scores matrix is published as a spreadsheet: Version 3 as an XLSX file and Version 2 as a CSV file1. Ofgem asks that questions about the scores or their application be sent to ECO@ofgem.gov.uk1.
Why it matters for households
The scores matrix is the mechanism that decides how much credit an energy company receives for a measure installed in a home. Because the scheme uses the ECO4 partial project scores framework, with ineligible measure types removed, the measures that carry scores are the ones companies have a route to fund through the scheme1. For a household, the practical effect is that the availability of a measure under the scheme follows the matrix, and the matrix has changed over time: hybrid wall insulation was added in July 2023 and smart thermostats in April 20251. The smart thermostat rules also tie eligibility to the heat source recorded for the home, since the PCDB lists such products only for certain gas and LPG boilers1. How any of this interacts with a particular property's assessment is set out in the scheme's eligibility rules and in the wider picture of insulation and energy independence.
What happens next
The page records no further dated steps beyond the update applicable to Version 3, dated 06 August 20251. No future version of the matrix has been reported1.