ECO4 Flex: Local Authority and NHS Referrals

The route most households use runs through an installer rather than the council. All potentially eligible households should apply through a TrustMark-registered or approved ECO or GBIS installer³. The headline criteria are a combined gross annual household income under £31,000, or a qualifying health or EPC position, with the property generally in SAP bands D to G for owner-occupiers².

What ECO4 Flex does for a household's energy independence is real but partial. It can fund insulation, heating and renewable measures that cut bills and reduce exposure to price swings, but it does not remove dependence on the grid, a supplier or the gas network, and it does not guarantee that funding is available even where eligibility is confirmed¹.

What ECO4 Flex is, and who it is for

ECO4 Flex is a referral mechanism, not a separate grant scheme. It sits inside ECO4 and lets local authorities and the Scottish and Welsh governments, referred to in the scheme as Devolved Administrations, identify low-income or vulnerable households who are not in receipt of the means-tested benefits that would make them eligible for ECO, but who may benefit from energy efficiency improvements². Councils participate voluntarily, and a council that has not published flexible eligibility criteria cannot refer anyone under the route¹.

The practical effect is that a household can reach funded measures without a benefit award. Households without benefits can qualify if they meet income, EPC rating or health-vulnerability criteria, and councils such as Oxford City and South Oxfordshire have published Flexible Eligibility routes on that basis⁷. Essex County Council frames its own version around a household identified by the council as vulnerable and not eligible under any other scheme⁸.

Two limits matter. First, eligibility for ECO4 does not guarantee that funding is available¹. Second, the referral is only the start: the measure still has to be installed by a registered business and the property still has to meet the scheme's improvement requirements. For a household, the value is that it opens a route to fabric and heating work that would otherwise be self-funded; the dependence that remains is on a participating council, an obligated supplier and an installer willing to take the job.

Who can refer: councils, devolved administrations and suppliers

The referral parties named in the scheme are local authorities and the Scottish and Welsh governments². Local authorities are also able to refer residents in their areas to obligated energy suppliers so that they can be offered support under ECO Flex². That means a council can act either by publishing criteria and assessing households, or by passing a household to a supplier.

Energy suppliers have their own referral group. Suppliers can refer households under ECO4 Flex where they are either struggling with persistent fuel debt and supported by suppliers, or using pre-payment meters and have regularly been unable to stay connected to their fuel supplies due to financial hardship². This is the fuel debt limb of the scheme, and it does not require the household to have approached the council first.

There are restrictions on who a council will deal with. Ceredigion County Council states that it does not accept referrals from lead generators or third parties¹. That matters in practice, because a household approached by a cold-calling intermediary may find the referral is not accepted at all.

Liability sits with the installer, not the council. Under ECO4 Flex, local authorities are not liable for any claims a customer makes should they be dissatisfied with the standard of work; liability is held with the installer¹. A household's route to redress therefore runs through the installer and its registration body, not through the council that signed the declaration.

The four routes: income, health, EPC band and fuel debt

ECO4 Flex operates through Route 1, Route 2, Route 3 and Route 4⁹. The routes are proxies: each describes a household or property circumstance that stands in for the means test. The health route is Route 3, and it requires the household to be identified and referred by a GP, a Health Board or an NHS trust¹.

The qualifying health conditions under Route 3 are a cardiovascular condition, a respiratory disease, limited mobility and immunosuppression⁵. The scheme also covers households identified as low income and vulnerable, with an occupant whose health conditions may be impacted further by living in a cold home, under the NHS referral route¹⁰. Derbyshire County Council describes the same group in similar terms¹¹.

The fuel debt limb appears as Proxy 6: a person in the household has been referred to the local authority for support by their energy supplier or Citizens Advice because they are struggling to pay their electricity and or gas bills¹. That proxy connects the supplier referral route to the council's own criteria.

Not every combination is allowed. The published guidance prohibits Proxy 1 with Proxy 3⁵. Where a household might qualify under more than one route, the installer or council checks which combination the rules permit before a declaration is made.

Eligibility at a glance: income, SAP bands and tenure

The income test is a combined gross annual household income under £31,000². Essex County Council states the same threshold as a household income below £31,000⁸. Independent guidance describes the Flex scheme as available where combined annual household income is under £31,000 and someone lives at the property with a qualifying long-term health condition¹².

The SAP band depends on tenure and route. For Routes 1, 3 and 4, owner-occupied properties qualify at SAP bands D to G⁴. For the same routes in the private rented sector, the band is E to G⁵. Ceredigion County Council describes its Route 1 group as E to G private rented sector households¹. Under the general ECO4 measures table, the private rented sector starting SAP band is E to G⁴.

Tenure is a hard gate. To benefit from ECO4 Flex, a household must own its own home or have the permission of its landlord¹. Essex County Council requires applicants to be living in Essex and to be a homeowner, private tenant or landlord, and residents of Southend and Thurrock are not eligible under its scheme⁸. That territorial limit is a reminder that Flex criteria are set council by council, so the same household can be eligible in one area and not in the next.

Social housing sits outside this route. ECO4's eligibility routes are the Help to Heat Group, Social Housing, LA Flex, In-Fill and Supplier Flex¹³. A social housing tenant should look at the social housing route and the landlord's own programmes rather than a Flex referral.

How to apply: installers, councils and approved providers

The standard application path is through an installer. All potentially eligible households should apply through a TrustMark-registered or approved ECO or GBIS installer³. Birmingham City Council's Statement of Intent repeats the same instruction³, and Ceredigion County Council directs households to contact one of its approved ECO4 Flex providers or agents¹. MCS Certified advises reaching out to an approved ECO4 supplier to express interest¹⁴.

Some councils do not take applications at all. Bridgend County Borough Council states that it will not be accepting any ECO related requests, and that residents assessed as potentially eligible are referred on to the relevant funding scheme provider or an approved installation company¹⁵. Where a council does process the referral, checking may be delegated: Bridgend states that information is provided to the council for checking via its ECO flex delivery partner, E.ON¹⁵.

Installer registration is not optional. Installations of most energy efficiency measures under ECO4 Flex must be carried out by TrustMark-registered businesses adhering to PAS standards¹. All ECO4 measures except DHC must be installed by, or under the responsibility of, a person registered with TrustMark or equivalent for the measure, and lodged with TrustMark or equivalent¹⁶.

What gets funded and the minimum EPC improvement

Funded measures under ECO4 cover insulation, boilers and central heating, and solar and renewable energy technologies¹⁰. All ECO4 eligible measures must be delivered to eligible domestic premises, including those delivered via LA Flex and in-fill, and eligible domestic premises include mobile homes⁵.

The improvement requirement is the part households most often miss. Properties with starting EPC bands F and G must be improved to an EPC D, while properties with starting EPC bands E and D must be improved to an EPC C¹. The delivery guidance states that any starting SAP band D or E property treated must be improved to at least a band C⁵.

Funding is tied to that improvement. The amount of ECO funding a property attracts is dependent upon the improvement made to the original Energy Performance Certificate¹¹. A property that cannot reach the required band may therefore attract less funding, or none.

Statements of Intent, evidence and record keeping

A Statement of Intent sets out a council's flexible eligibility criteria for ECO4 Flex¹⁵. Each council publishes its own, and versions differ: Ceredigion County Council works in accordance with version 4 of its ECO4/GBIS Flex Statement of Intent¹, while Birmingham City Council's document is version 7.0³. A household checking its own council's criteria should look for the current published version, because a superseded document may describe routes the council no longer operates.

Record keeping runs long. Applications and declarations may be subject to Ofgem audits during the time ECO4 is in effect and up to three years after the schemes end¹. The declaration itself must be issued within the 12-month period preceding the day on which the project or measure is complete⁴. For a household, that means keeping the paperwork for the installation, the declaration and the EPC well after the work is finished.

The scheme has a defined end. The ECO4 scheme period runs to 31 March 2026¹⁷. Councils also review their Flex pages on their own cycles; one published page carries a next review date of 02 September 2027¹⁸.

For households in the private rented sector, the permission requirement and the E to G band interact with the landlord's own duties, which are covered in Renting and Home Energy and Asking a Landlord for Energy Improvements. Households in social housing should start from Energy in Social Housing, and those weighing up what funded work can achieve for a low-income household will find the wider picture in Help for Low-Income Households in England and Fuel Poverty in the UK.