Ofgem published a summary of proposed administration changes to the Energy Company Obligation scheme (ECO4) and the Great British Insulation Scheme (GBIS) on 7 April 2025, alongside a consultation on how it will administer policy decisions set out by government1. The consultation opened on 7 April 2025 and closes on 12 May 2025, a five-week window2. Ofgem states that the summary document is published on a draft basis and "should not be followed until full guidance documents are published following the consultation period"1.
The proposed changes follow the government response to the mid-scheme changes consultation, published on 7 April 20252. ECO4 and GBIS commenced on 1 April 2022 and 31 March 2023 respectively, and are due to end concurrently on 31 March 20262. Among the changes is an increase in the number of insulation measures that can be installed within a GBIS project to two measures2. Any two of cavity wall, loft, underfloor, solid floor or pitched roof insulation may be installed in a single property in specific circumstances; both must form part of the same retrofit, be promoted by the same supplier, be completed on or after 14 November 2024, and the second must be completed within three months of the first and no later than 31 March 20262. Smart thermostats will be introduced as their own measure type in GBIS, enabling delivery as a secondary measure in owner occupied low-income households, subject to the Boiler Plus Standard criteria2.
On scheme obligations, suppliers must deliver at least 25% of their GBIS obligation through GBIS measures and may deliver up to 75% through ECO4 projects1. Each ABS delivered through ECO4 will be worth 1.251 ABS in GBIS, and measures reassigned will be subject to a conversion factor of 1.7161. Government has also removed GBIS annual targets1.
On installation standards, the transition period between PAS 2035/2030:2019 and PAS 2035/2030:2023 ended on 30 March 2025, and from that date the old standards are no longer applicable and only the new standards can be used1.
"We are consulting on our proposed administrative approach to mid-scheme changes to the current Energy Company Obligation scheme (ECO4) and the Great British Insulation Scheme (GBIS), as set out by government."
| Proposed change | Detail |
|---|---|
| GBIS insulation measures per project | Up to two, from 14 November 2024 |
| Second measure deadline | Within 3 months of the first, and by 31 March 2026 |
| Smart thermostats | New measure type in GBIS, secondary measure for owner occupied low-income households |
| GBIS obligation split | At least 25% via GBIS measures, up to 75% via ECO4 |
| ECO4 ABS reassigned to GBIS | 1.251 ABS per ABS; conversion factor 1.716 |
Why it matters for households
ECO4 and GBIS are the two main routes through which insulation and heating measures are funded by energy suppliers under obligation. The proposal to allow two insulation measures in a single GBIS project changes what a household can receive under one retrofit, and the three-month rule between the first and second measure sets a timetable for the work. The introduction of smart thermostats as a GBIS measure type widens the range of measures available under that scheme for owner occupied low-income households, subject to Boiler Plus criteria. The rules on reassigning ECO4 ABS to GBIS affect how suppliers account for delivery, which in turn shapes where they direct funding. The draft status of the guidance means the detail may change before it takes effect, and Ofgem has said the summary should not be followed until full guidance is published1.
What happens next
Ofgem will request a plan from suppliers on any ECO4 ABS they intend to reassign to GBIS in a first window in early summer (May/June) 2025, and a second window in November 2025 will request an update from suppliers1. Suppliers will be required to formally request reassignment to Ofgem by 31 July 2026, and will be notified of the final determination no later than 30 September 20261. Ofgem states it will notify all suppliers of its final determination before 1 December 20261. The consultation closes on 12 May 20252.