Rolling submissions for ECO4 to GBIS reassignment open

Ofgem has set out that it will allow rolling submissions for the reassignment of Energy Company Obligation (ECO4) delivery to the Great British Insulation Scheme (GBIS) from 30 April 2026¹. The change appears in version 3.1 of the ECO4 Guidance: Supplier Administration, published on 6 July 2026, which covers the processes suppliers and Ofgem follow under the ECO4 Order¹.

ECO4 commenced on 27 July 2022 and runs until 31 December 2026¹. Ofgem administers the scheme on behalf of the Gas and Electricity Markets Authority, and the guidance applies to all measures installed from 1 April 2022¹. Under the scheme, obligated energy suppliers must achieve annual cost savings of £224.3 million under the Home Heating Cost Reduction Obligation (HHCRO), with the target divided between suppliers according to their share of the domestic gas and electricity market¹. The HHCRO target must be achieved no later than 31 December 2026¹.

The guidance sets out the deadlines that apply to the reassignment process and to the wider scheme:

Ofgem states that suppliers are required to formally request reassignment by 31 July 2026, and that it will notify all suppliers of its final determination no later than 30 June 2027¹. The guidance also states that installation extensions will not allow installation dates beyond the overall scheme deadline of 31 December 2026, and that all measures must be notified before 1 April 2027 regardless of any notification extensions¹.

"We will allow rolling submissions from 30th April 2026"

The guidance describes reassignment as the process of moving ECO4 delivery towards GBIS, and covers the two conversion factors applied to reassigned ECO4 delivery and to GBIS delivery over 25 per cent, along with the impact on ECO4 and GBIS sub obligations and any compliance action or rejections relating to reassigned delivery¹. The document also addresses carry-over of ECO3 measures, early delivery, trading obligations, notification of measures and transfers of qualifying actions¹.

Why it matters for households

ECO4 is the route through which insulation and heating measures are installed in low income and vulnerable households, with a focus on whole house retrofits¹. Reassignment moves delivery from ECO4 to GBIS, so the practical effect for a household is which scheme funds the work and which rules apply to it. The two schemes differ in eligibility and in the measures they support, and the Great British Insulation Scheme vs ECO4 comparison sets out those differences.

For a home, the timing matters as much as the scheme. The overall ECO4 deadline of 31 December 2026 and the notification deadline of 1 April 2027 mean the window for measures delivered under ECO4 rules is closing¹. Households considering measures alongside other government funding can check how schemes combine under Can ECO4 measures be funded with other government grants?, and the current scheme rules are set out under ECO4: The Current Energy Company Obligation Scheme. Insulation and heating measures are the core of both schemes; solar panels are not part of ECO4 delivery as described in this guidance, and the position on them is covered under Can You Get Solar Panels Through ECO4?. Boiler-related support is addressed under Can I get a free boiler grant under ECO4?.

What happens next

Suppliers must formally request reassignment to Ofgem by 31 July 2026¹. All transfer applications for measures and projects must be submitted on or before 31 March 2027, and all measures must be notified before 1 April 2027¹. Ofgem will notify all suppliers of its final determination no later than 30 June 2027¹. The guidance does not state how many suppliers intend to request reassignment, or what proportion of ECO4 delivery is expected to move to GBIS; those figures have not been reported¹.

Sources1 cited

1. ECO4 Guidance: Supplier Administration, ofgem.gov.uk