ECO4-Programm: Energieeffizienz 2026 (GB)

The Energy Company Obligation (ECO4) is the fourth iteration of the UK government's flagship demand-side energy efficiency programme, running from April 2022 to March 2026. Under ECO4, Ofgem places a legal obligation on larger energy suppliers — those with 150,000 or more domestic customers — to fund and deliver energy efficiency improvements in the least energy-efficient and most fuel-poor homes across Great Britain. For architects and building designers specialising in social housing, affordable housing, or retrofit projects, ECO4 represents a significant source of funding for clients who would otherwise be unable to afford fabric improvements or heating system upgrades.

Households eligible for ECO4 support must typically be in receipt of qualifying means-tested benefits (such as Universal Credit, Pension Credit, or Child Tax Credit) or be identified as fuel-poor through the Flexible Eligibility (LA Flex) route, whereby local authorities can refer households that do not receive benefits but are nonetheless in fuel poverty. Properties must have an Energy Performance Certificate (EPC) rating of D, E, F, or G at the point of referral. The overarching aim is that each property is improved to at least an EPC Band D upon completion of works — making whole-house retrofit planning a central part of any ECO4-funded project.

Eligible measures under ECO4 include solid wall insulation (internal and external), cavity wall insulation, loft insulation, underfloor insulation, heat pump installations, solar photovoltaic panels, and heating controls. Crucially, ECO4 takes a fabric-first approach: insulation measures must generally be installed before or alongside low-carbon heating systems. This has direct implications for design specifications, as architects must ensure building fabric performance is addressed holistically. The funded measures are delivered at no upfront cost to the eligible household, with energy suppliers commissioning their own approved installer networks.

Architects and designers can support ECO4 delivery by conducting or commissioning whole-house retrofit assessments (using PAS 2035:2019 as the governing standard), acting as or appointing a Retrofit Coordinator, and ensuring that design proposals align with the scheme's technical requirements. Referrals to energy suppliers or their managing agents can be made via local authority Flex routes or directly through supplier portals. With ECO4 closing in March 2026, design teams should also monitor announcements regarding the successor scheme (expected to be ECO5 or a similar obligation) to maintain continuity of funding pathways for clients.

Note: This article is not a substitute for legal or professional advice. Please consult a qualified expert for advice specific to your project or circumstances.

Umsetzungs-Checkliste

1. Identify whether the client household is in receipt of qualifying benefits or can be referred via Local Authority Flex eligibility
2. Commission a current EPC to confirm the property is rated D, E, F, or G
3. Engage a PAS 2035-compliant Retrofit Coordinator to assess the property and produce a whole-house retrofit plan
4. Specify fabric-first measures (insulation) prior to or alongside low-carbon heating system upgrades
5. Contact obligated energy suppliers or their managing agents to register the property for ECO4 funding
6. Ensure all installers hold relevant TrustMark and MCS certifications where applicable
7. Document all works with an updated EPC upon completion to confirm uplift to at least Band D
8. Monitor government announcements for the ECO4 successor scheme ahead of the March 2026 closure