ECO4 Scheme: Fenster & Dämmung (GB)

The Energy Company Obligation 4 (ECO4) scheme is a government-backed programme administered by Ofgem that places a legal obligation on large UK energy suppliers (those with 150,000+ domestic customers) to deliver energy efficiency measures to low-income and vulnerable homes. Running from April 2022 to March 2026, ECO4 takes a whole-house, fabric-first approach — meaning glazing, doors and insulation measures are funded as part of a comprehensive retrofit rather than as standalone measures.

Eligibility is targeted at households receiving means-tested benefits such as Universal Credit, Pension Credit, or Child Tax Credit, as well as properties referred through the ECO4 Flex route, where local authorities can extend eligibility to fuel-poor households not on qualifying benefits. Social housing landlords may also access the scheme under certain conditions. For window and door installers, this means working through an Ofgem-approved energy supplier or a TrustMark-registered retrofit coordinator to access ECO4 funding on behalf of their customers.

Under ECO4, replacement windows and doors must meet minimum energy performance standards — typically achieving at least a BFRC (British Fenestration Rating Council) Window Energy Rating of Band C or above. Double or triple glazing replacing single glazing is the most common qualifying scenario. Measures must be installed by a TrustMark-accredited or MCS-certified installer, and all works are subject to a PAS 2035 assessment carried out by a qualified retrofit assessor, ensuring the improvement fits within the property's overall energy strategy.

To access ECO4 funding, homeowners or tenants should first check eligibility via the government's Simple Energy Advice (SEA) service or contact their energy supplier directly. Installers and contractors in the fenestration industry should register with TrustMark and align with PAS 2035/2030 standards to become eligible ECO4 delivery partners. Suppliers then commission the work through their obligation delivery chains. It is strongly recommended that businesses contact Ofgem and relevant energy suppliers early, as the scheme is due to close in March 2026 and successor arrangements (ECO5 or a Great British Insulation Scheme successor) are subject to government consultation.

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

Umsetzungs-Checkliste

1. Verify household eligibility via the Simple Energy Advice (SEA) portal or energy supplier
2. Register your business with TrustMark to become an ECO4-approved installer
3. Ensure all window/door products meet minimum BFRC Band C energy rating
4. Commission a PAS 2035 retrofit assessment before works begin
5. Partner with an Ofgem-obligated energy supplier or approved ECO4 delivery body
6. Complete all installations to PAS 2030 quality standards
7. Submit post-installation documentation and energy performance evidence to the delivery chain
8. Monitor ECO4 closure (March 2026) and prepare for successor scheme announcements