Ofgem published version 1.1 of the ECO4 Delivery Guidance on 3 February 2023, setting out further clarification on Solar PV, Child Benefit and local authority Flex suitable evidence, hybrid heat pumps and electric heating systems1. The guidance sets out the regulator's procedures for administering the Electricity and Gas (Energy Company Obligation) Order 2022, which places legal obligations on energy suppliers to deliver energy efficiency measures to domestic premises, with each supplier holding a target based on its share of the domestic energy market in Great Britain1.
The v1.1 revision relates to further clarification on Solar PV, Child Benefit and LA Flex suitable evidence, hybrid heat pumps and electric heating systems1. The document states that the overall obligation period for ECO4 runs from the commencement date of the ECO4 Order on 27 July 2022 to 31 March 20261. It also records that ECO3 Interim Delivery allowed suppliers to deliver to ECO3 rules and ECO3 scoring methodology for three months between 1 April 2022 and 30 June 20221.
On eligibility, the guidance states that ECO measures delivered to premises occupied by a member of the Help To Heat Group or identified through the ECO4 Flex route must be delivered to private domestic premises1. It sets out that new evidence requirements come in from 1 April 20231. On rural and off-gas premises, it states that projects delivered in rural off-gas properties in Wales and Scotland will receive an uplift of 35 per cent, and that in England an uplift for measures delivered to off-gas premises will not apply as these homes are expected to receive support under the Home Upgrade Grant1. In Wales, the Rural Urban Indicator Codes D1, D2, E1, E2, F1 and F2 qualify as rural areas1.
The guidance also covers the treatment of particular property types and tenures, including crofts, houses in multiple occupation and the private rented sector. It states that care homes and student halls of residence will not be eligible for ECO4 measures as these are commercial properties, while houses in multiple occupation can be treated as part of ECO4 if at least one household occupying the HMO is eligible to receive ECO support1. On transfers, it states that suppliers may also transfer measures to another obligated supplier if all measures that are linked in a project are transferred together1.
Ofgem has since published later versions of the guidance. A summary of updates records version 2.0 with a publication date of 14 August 2023, version 2.1 on 5 April 2024, version 3.0 on 7 August 2025, version 3.1 on 10 October 2025 and version 3.2 on 8 December 20252. A later summary records version 4.0 with a publication date of 26 March 2026, reflecting the extension of ECO4 by nine months to 31 December 20263. The same summary records that the Great British Insulation Scheme closed on 31 March 20263.
Why it matters for households
ECO4 is the mechanism through which energy suppliers fund insulation, heating and other efficiency measures in low income and vulnerable households, so the delivery guidance determines which homes can receive ECO4 support and on what evidence. The v1.1 clarifications on Solar PV, Child Benefit and Flex evidence, hybrid heat pumps and electric heating systems affect what paperwork a household must produce and which technologies count towards a supplier's obligation1. The rural off-gas uplift of 35 per cent in Wales and Scotland, and its absence in England where the Home Upgrade Grant applies instead, means the value a project carries varies by nation and by whether the home is connected to the gas grid1. The rules on private domestic premises, tenure and property type determine whether a given home is eligible at all1. Ofgem's role in administering the scheme, including the evidence it accepts and the audits it runs, is set out in its regulator guidance, and the scoring rules that decide whether a project qualifies are covered in the guidance on ECO4 scoring and minimum requirements.
What happens next
The guidance has been revised repeatedly since v1.1. Version 2.0 was published on 14 August 2023, version 2.1 on 5 April 2024, version 3.0 on 7 August 2025, version 3.1 on 10 October 2025 and version 3.2 on 8 December 20252. Version 4.0, published on 26 March 2026, reflects the extension of ECO4 by nine months to 31 December 20263. The same summary records that the Great British Insulation Scheme closed on 31 March 20263.
Sources3 cited
- ECO4 delivery guidance, ofgem.gov.uk
- ECO4 Delivery Guidance & Measures Table Summary of Updates, ofgem.gov.uk
- ECO4 Delivery Guidance & Measures Table Summary of Updates, ofgem.gov.uk