Energy Company Obligation (ECO4) Guidance: Supplier Administration
Summary
Ofgem has updated its ECO4 supplier administration guidance to reflect the government's nine-month extension of the scheme deadline to 31 December 2026. The guidance covers obligation setting, measure notification, trading, transfers, and reassignment of bill savings between ECO4 and the Great British Insulation Scheme. No structural changes to the scheme — this is administrative housekeeping for an existing supplier obligation.
Why it matters
ECO4 is a redistributive programme that socialises insulation costs across energy bills via supplier obligations. The deadline extension gives obligated suppliers more time to deliver but does not change the cost allocation mechanism or market structure.
Key facts
- •ECO4 Order commenced 27 July 2022
- •Deadline extended by nine months to 31 December 2026
- •Guidance last updated 8 December 2025
- •Covers solid wall minimum requirement, EFG minimum requirement, obligation trading and transfers
- •Bill savings can be reassigned from ECO4 to GBIS
Timeline
Areas affected
Related programmes
Memo
Energy Company Obligation (ECO4) Guidance: Supplier Administration | Ofgem Please enable JavaScript in your web browser to get the best experience. BETA This site is currently in BETA. Help us improve by giving us your feedback . Close alert: Energy Company Obligation (ECO4) Guidance: Supplier Administration Publication type: Guidance Publication date: 7 August 2025 Last updated: 8 December 2025 Scheme name: ECO Print this page Related links ECO guidance and associated documents Share the page Share on Facebook Share on Twitter Share on LinkedIn The Energy Company Obligation (ECO) is a government energy efficiency scheme for Great Britain, administered by Ofgem. Our guidance documents provide information on the legislative requirements of the ECO4 Order and our administrative processes. The ECO4 Order commenced on 27 July 2022 and runs until 31 December 2026. ECO4 Guidance: Supplier Administration ECO4 Guidance: Delivery Great British Insulation Scheme and ECO4: Local Authority Administration Guidance ECO4 Guidance: New Measures and Products The Supplier Administration guidance is aimed mainly at suppliers, describing the processes that suppliers and Ofgem follow to meet the requirements of the ECO4 Order. It addresses the following: when a supplier is obligated under ECO4, notifying customer numbers and supply and how obligations are set details of the solid wall minimum requirement details of the EFG minimum requirement how suppliers notify completed ECO measures and projects carry-over, interim and early delivery of measures the application process for trading obligations the application process for transfers details on reassigning annual bill savings from ECO4 to GBIS details on the end of the obligation period and achieving your obligation our role as the ECO administrator For measures installed before 1 April 2022, please refer to our ECO3 Guidance: Supplier Administration, Version 1.3. This guidance document has been updated to reflect the government’s extension of ECO4 deadline by nine months, to 31 December 2026. Further details of the updates contained in this version are provided in the separately published subsidiary document below. Main document ECO4 Guidance - Supplier Administration [PDF, 805.42KB] Subsidiary documents Summary of Updates - ECO4 Guidance Supplier Administration [PDF, 188.59KB] Print this page Related links ECO guidance and associated documents Share the page Share on Facebook Share on Twitter Share on LinkedIn Close