Key takeaways
- ECO4 funds insulation, heat pumps, solar PV and ventilation for low-income households — but rarely as standalone measures.
- There are four eligibility routes: benefit-led, NHS LIFT referral, Local Authority Flex, and Innovation measures.
- The scheme closes for new applications in March 2026 and is being replaced by GBIS Plus.
- Most rejections come from EPC mismatch, partial benefit data, or the property already having target measures installed.
- ECO4 will not retrofit a home that is already EPC C or above — it is targeted at D, E, F and G properties.
ECO4 — the Energy Company Obligation 4 — is the largest active home energy grant scheme in the UK by funding pool. It is a legal obligation placed on energy suppliers (not a Treasury grant), which is why the application process runs through accredited installers and managing agents rather than councils or central government portals.
For a typical fuel-poor household, ECO4 can pay for a deep retrofit worth £8,000 to £25,000 with no contribution from the homeowner. But because the scheme is targeted at the worst-performing homes and lowest-income households, eligibility is narrower than most public coverage suggests.
What ECO4 actually is
The Energy Company Obligation is a regulatory scheme under the Electricity and Gas (Energy Company Obligation) Order. The fourth iteration (ECO4) began on 1 April 2022 and runs to 31 March 2026. Suppliers with more than 150,000 domestic customer accounts are obliged to deliver a set quota of energy savings, measured in lifetime bill savings (the "ABS" target).
The pool is funded by all GB energy bill payers — roughly £4 billion across the four-year period, recovered through standing charges and unit rates. Households do not see the cost on their bills as a separate line item.
Suppliers contract with managing agents (such as E.ON Next, Octopus, Warmworks, Sustainable Building Services) who in turn use accredited installers to deliver the measures. The supplier reports the savings to Ofgem and gets credited against its obligation.
The defining feature of ECO4 is the "whole-house" approach. Unlike ECO3, which funded individual measures, ECO4 requires installers to deliver a package that lifts the property by at least one EPC band, with most homes targeted to reach Band D or C.
Eligibility — the four routes
There are four ways into ECO4. A household needs to qualify under one of them.
| Route | Who qualifies | Evidence required |
|---|---|---|
| Benefit-led (Affordable Warmth) | Households receiving means-tested benefits — Universal Credit, Pension Credit, ESA, JSA, Income Support, Working Tax Credit, Child Tax Credit, Housing Benefit | Recent award letter or DWP Data Sharing match |
| NHS LIFT referral | Households where a resident has a health condition worsened by cold (respiratory, cardiovascular, mental health, immunosuppression, mobility-limiting) | GP, district nurse, OT, social prescriber referral via the LIFT framework |
| Local Authority Flex | Households the LA has identified as fuel-poor or vulnerable, even if not on the benefits list — defined in each LA's Statement of Intent | Council-issued declaration; rules vary by LA |
| Innovation Measures | Properties used for early-stage trials of novel measures (e.g. low-carbon heating with smart controls); set quota only | Installer-led, household passive |
Roughly 70% of ECO4 measures to date have come through the benefit-led route. LA Flex has grown to around 22%, and NHS LIFT to under 5%.
The household must also be the right tenure. Owner-occupiers, private tenants (with landlord consent and a contribution), and most social tenants are eligible. Park homes have a separate carve-out.
Property eligibility — the EPC band rule
ECO4 will not pay to upgrade a home that is already at EPC Band C or above. The scheme is explicitly targeted at the worst-performing homes — Band D, E, F and G — with the deepest retrofits reserved for F and G.
The property's pre-installation EPC must be valid and on the official register. A typical fuel-poor household with a 2008-era EPC may need a fresh assessment before the application can proceed. Some installers will pay for this; many will not.
The "uplift target" is set per band. A Band G home should reach at least Band D. A Band E home should reach at least Band C. This is why ECO4 typically funds packages — single measures rarely deliver the required uplift on poor-performing homes.
Higher spend on F and G homes reflects the depth of retrofit needed — solid wall insulation, full heating system replacement, and sometimes ventilation upgrades together.
What ECO4 will pay for
The scheme funds a defined list of measures, all of which must be installed by a TrustMark-registered installer using PAS 2035 retrofit standards.
| Measure | Typical funded value | Notes |
|---|---|---|
| Loft insulation | £500 - £1,200 | Up to 270mm depth; almost always part of a package |
| Cavity wall insulation | £600 - £1,400 | Subject to pre-install inspection for damp/condensation risk |
| Solid wall insulation (internal or external) | £8,000 - £18,000 | External preferred where possible; internal disrupts the household |
| First-time central heating | £3,500 - £6,500 | For homes with no existing wet system — typically gas connection and boiler |
| Air source heat pump | £8,000 - £14,000 | Where mains gas is not present or the household opts for electric |
| Solar PV | £3,500 - £6,500 | Restricted to electrically-heated homes under ECO4 rules |
| Mechanical ventilation | £800 - £2,000 | Often required after deep insulation work to manage humidity |
| Window and door upgrades | Limited | Single-glazed to double; not as standalone |
Boiler replacement on a like-for-like gas basis is no longer eligible under ECO4 for households with an existing working boiler, even an inefficient one. This was a significant change from ECO3 and remains a common source of confusion.
How to apply
There is no government portal. ECO4 applications run through installers and managing agents, who do their own eligibility assessment.
- Eligibility self-check. Run through the criteria against the four routes. Confirm the household receives a qualifying benefit, has an LA Flex declaration available, or has a health condition that meets NHS LIFT.
- Locate the EPC. Search the EPC register at gov.uk/find-energy-certificate. If it is missing or older than 10 years, expect to commission a new one — typically £80-£120, sometimes covered by the installer.
- Find an accredited installer. Use TrustMark's directory or a managing agent's installer list. Avoid cold-callers — most ECO4 fraud reported to Ofgem starts with a doorstep approach.
- Survey and quote. The installer will conduct a PAS 2035 retrofit assessment, design the package to deliver the required EPC uplift, and submit it to the managing agent for approval.
- Approval and install. Approval takes 2-8 weeks. Install runs 1-12 weeks depending on measure depth.
- Lodgement. The installer lodges the measure with TrustMark and the managing agent. The household receives a new EPC reflecting the uplift.
Common reasons applications get rejected
| Reason | Frequency | What to do |
|---|---|---|
| EPC already at C or above | ~28% | ECO4 is closed to you. Look at GBIS or wait for GBIS Plus. |
| Benefit data not on DWP share | ~17% | Provide a recent award letter to the installer to override the data check. |
| Property tenure mismatch | ~12% | Private tenants need landlord consent and a contribution — typical 25-50% of measure cost. |
| Whole-house uplift not achievable | ~10% | The property needs more measures than the budget allows. Sometimes a partial install is offered with a contribution. |
| LA Flex declaration not accepted | ~9% | The LA's SoI may not match the route the installer claimed. Ask the LA energy officer to clarify. |
| Existing measures present | ~8% | If loft insulation is already 200mm+, the installer cannot claim it again. |
| Damp or structural issues | ~7% | Pre-existing damp must be remediated first — out of scope for ECO4. |
| Mains gas reconnection required | ~5% | First-time central heating is funded but the gas connection itself often is not. |
| Other | ~4% | Including paperwork errors, identity mismatches, contested ownership. |
The single most common pattern among rejected applications is the household assuming a benefit award letter alone is enough. The installer needs to be able to evidence the benefit on the day of survey — a letter from 14 months ago will usually fail the check.
Why ECO4 is ending
The scheme has been formally extended once already (from a planned end of March 2025 to March 2026 to absorb pipeline delays). It will not be extended again.
The Department for Energy Security and Net Zero (DESNZ) has consulted on a successor scheme provisionally branded GBIS Plus, due to begin in April 2026. The shape is still being decided, but the design direction is:
- Broader eligibility — includes households not on benefits but in council tax bands A-D with EPC D or below.
- Narrower measure list — focus on insulation and heating controls, with heat pumps split off into BUS-3.
- Per-property cap — likely £6,000 - £10,000 rather than ECO4's whole-house budget.
- Stronger consumer protection — TrustMark and PAS 2035 plus a new doorstep-selling ban.
The practical implication for households now: if you may qualify under ECO4, apply before the autumn 2025 cut-off, when most managing agents stop accepting new files to ensure they can deliver and lodge before March 2026.
LA Flex statements of intent
Each Local Authority that participates in ECO4 LA Flex publishes a Statement of Intent (SoI) listing the criteria under which it will issue a flex declaration. As of May 2026, around 240 of 333 English LAs participate, alongside most Welsh and Scottish councils.
Common LA Flex routes include:
- Annual gross household income below £31,000 (some LAs go to £36,000 in the South East).
- Resident has a health condition on the LA's vulnerability list.
- Property is on the LA's fuel poverty index in the bottom 30%.
- Household includes a child under 5 or an adult over 70.
- Combination criteria — for example, low income and EPC F or G.
The full SoI is usually published on the LA's housing or environment page. If it is not findable, the LA's energy officer (sometimes called sustainability officer or affordable warmth officer) can issue one on request.
ECO4 remains the most generous home energy grant available to fuel-poor UK households, but it closes in March 2026 and the eligibility window is narrowing as managing agents close their books. If your home is EPC D or below and someone in the household receives means-tested benefits or has a relevant health condition, it is worth checking eligibility in the next few months rather than waiting.
For a 60-second eligibility self-check covering ECO4, GBIS, BUS, SEG and LA Flex routes in one pass, run through the Green Home Grants eligibility checker. If you would prefer to speak to an independent retrofit assessor before applying, the assessor directory at Healthy Homes Network lists qualified PAS 2035 assessors by region.
Want to know if you actually qualify? Run our 7-question eligibility checker →