Ofgem published version 3.2 of the ECO4 Delivery Guidance on 8 December 2025, setting out how the scheme administrator will treat non-compliant measures and how rural properties are identified in Scotland1.
The update states that it clarifies "the circumstances when we will seek to reject non-compliant measures" and "how to define rural areas in Scotland", alongside general formatting and drafting improvements1. On non-compliance, new wording in paragraphs 4.55-4.56 and 5.256 confirms that Ofgem will refer measures to rejections when the TrustMark certificate of lodgement has been voided, and describes how supplier representations will be handled in such cases1. On rural definition, the guidance clarifies the datasets and classifications used to identify rural properties in paragraphs 3.69-3.721.
The rural clarification sits within a longer sequence of changes. Version 3.0, published 7 August 2025, added paragraphs 3.69 and 3.70 to define a "rural area" for projects completed before and after the coming into force date of the ECO Order 2025, updated paragraph 3.72 to reflect changes to rural data sets, and added paragraphs 3.73-3.75 to set out the relevant Rural Indicator Codes for England and Wales and the relevant Rural Classifications for Scotland1. Version 2.1, published 5 April 2024, had already addressed "the correct datasets to use to determine rural premises" in paragraphs 3.70 and 3.721.
Version 3.2 followed version 3.1, published 10 October 2025, which contained general formatting and drafting improvements only1. A later version, 4.0, was published on 26 March 2026 and reflects "the extension of ECO4 by nine months to 31 December 2026"2. That version also records that the Great British Insulation Scheme closed on 31 March 2026, and that Working Tax Credit and Child Tax Credit ceased to exist on 5 April 2025, with receipt remaining legitimate evidence until 4 April 2026 under the 12-month rule2.
| Guidance version | Publication date |
|---|---|
| 2.1 | 5 April 2024 |
| 3.0 | 7 August 2025 |
| 3.1 | 10 October 2025 |
| 3.2 | 8 December 2025 |
| 4.0 | 26 March 2026 |
"These updates clarify the circumstances when we will seek to reject non-compliant measures, how to define rural areas in Scotland."
Why it matters for households
ECO4 is the obligation that funds insulation and heating measures in qualifying homes, so the guidance governs what an installer can put forward and what evidence a household must supply. The rural definition matters because rural status affects how a property is treated under the scheme, and Scotland's rural classifications differ from the Rural Indicator Codes used in England and Wales1. Households in rural and island areas face distinct cost and fuel poverty patterns, which the nations hub and the guide to how fuel poverty differs between rural and urban areas in Scotland set out. The TrustMark clarification matters because a voided certificate of lodgement can now lead to a measure being referred for rejection, which affects whether completed work is signed off under ECO4.
What happens next
Version 4.0, published 26 March 2026, reflects the extension of ECO4 to 31 December 20262. The guidance does not state what further versions are planned, and no further publication dates beyond version 4.0 have been reported2.