31 Dec 2026
ECO4 end date
Extended by 9 months in 2025
150,000+
Supplier threshold
Customers needed to be obligated
EPC D
Minimum target
Typical post-works rating
10,000
Typical full-home value
Insulation plus heating package
Which ECO route fits you?
Three short questions. We tell you whether ECO4, the Great British Insulation Scheme, the Boiler Upgrade Scheme or the Warm Homes Local Grant is your most realistic route this year.
Routes verified May 2026. Source: Ofgem ECO4 and GBIS guidance, gov.uk/apply-boiler-upgrade-scheme, gov.uk Warm Homes Local Grant. Best estimate only; your installer and energy supplier have the final say.
The belief most readers carry
The "free boiler" headline is misleading
Search "free boiler grant" and you will find a flood of pages, ads and phone-bank pitches promising a no-cost gas boiler if you receive any benefit. The promise is not exactly a scam, but it is not exactly true either. The version of ECO that ran from 2018 to 2022 (ECO3) did fund a fair number of boiler-for-boiler swaps, much like the earlier Green Homes Grant. ECO4 deliberately moved away from that. Ofgem rewrote the rulebook to push suppliers towards whole-home, multi-measure plans that lift the property up to a minimum EPC band, usually D or C.
In practice that means an eligible household whose boiler has just died will often not get a free replacement boiler on its own. They get a survey, an EPC assessment, and a plan that bundles insulation with the heating upgrade. If the maths do not work, the installer walks away. If the maths do work, you might end up with a heat pump, a smart thermostat and three rooms of insulation instead of the like-for-like swap you were expecting.
That gap between expectation and policy is where most of the disappointment, and most of the rogue-trader cold calls, live. The rest of this guide walks through how ECO4 actually works in 2026, what is changing in December, and what to do depending on which route is genuinely open to you.
Where standard guides fail
Three things most ECO articles get wrong
The scheme has been rewritten twice in four years. Most online content describes a version that no longer exists.
"ECO is a government grant"
It is not. ECO is a supplier obligation: Ofgem requires large energy suppliers to fund energy-efficiency works for fuel-poor households. The cost is recovered through every customer's bill, not through general taxation. From 2027 the model flips, and the Treasury takes over.
"You get a free boiler"
Sometimes. Usually not. ECO4 forces whole-home plans that bundle insulation with heating, aiming for a minimum EPC band uplift. A boiler-only swap is the exception, not the rule. The pages promising one are mostly lead generators, not delivery partners.
"ECO5 is coming"
It is not. The November 2025 Budget confirmed there is no successor supplier obligation. The Warm Homes Plan takes over from 2027, funded by roughly £15bn of Treasury capital. Different model, different routes, different timing.
How the scheme actually works
How ECO4 is actually funded, and why that matters
Every household with an energy bill is paying for ECO. That is by design, and it is about to end.
ECO4 is a cross-subsidy obligation. Ofgem sets each large supplier (those with more than 150,000 domestic customers) an annual savings target, measured in lifetime bill savings for low-income households. To hit the target, suppliers fund insulation surveys, install measures, and pay accredited installers. They recover the cost through every customer's energy bill, which is why your standing charges and unit rates carry a small ECO levy whether you ever benefit from the scheme or not.
That design has two consequences worth understanding. First, the scheme is structurally regressive at the margins: low-income households who do not happen to qualify for ECO works still pay the levy on their own bills, funding works for other low-income households. Second, the budget is fixed annually, once a supplier hits its target, the incentive to install another measure drops sharply, which is why installer capacity tightens visibly each February and March as the compliance year closes.
What happens after 31 December 2026
ECO4 was originally due to end on 31 March 2026. In 2025 Ofgem and the Government agreed a nine-month extension to 31 December 2026, not to add measures, but to give installers time to finish in-flight projects and remediate non-compliant installs. Targets were not increased. The Great British Insulation Scheme (GBIS), which ran alongside ECO4 as a single-measure top-up, still closes on 31 March 2026. ECO4 ABS-eligible measures can count towards GBIS targets for up to four months after that, until 31 July 2026.
From 2027 onwards the Warm Homes Plan takes over: a Treasury-funded, grant-based programme worth roughly £15bn over the spending review period. The model is fundamentally different. Money flows from general taxation, not from energy bills. Eligibility, measure mix and installer routes are all being redesigned, and the early signals suggest a heavier weighting towards heat pumps, solar and household-level deep retrofit rather than the multi-measure insulation packages that dominate ECO4. If you might qualify, the route and amounts will not be the same in 2027 as they are now.
ECO4 versus GBIS, which one applies to you
The two schemes overlap, but they target different households and pay for different things. ECO4 is the whole-home, low-income route. GBIS is a single-measure top-up with a wider catchment.
ECO4
Whole-homeCloses 31 December 2026. Funds insulation plus heating together to lift the property up to a minimum EPC band. Two routes in:
- Core ECO4, households on means-tested benefits (Pension Credit, UC, ESA, JSA, IS, HB, CTC/WTC);
- LA Flex, referred by your local authority as low-income or cold-sensitive, even without being on benefits.
GBIS
Single measureCloses 31 March 2026. Funds one insulation measure (loft, cavity wall, etc.). Two groups:
- General Group, EPC D to G and council tax band A to D in England, A to E in Scotland and Wales. No income test;
- Low-Income Group, means-tested benefits or LA Flex, EPC D to G.
What ECO4 actually funds
ECO4 measures fall into three groups: insulation, heating upgrades and controls. They are almost always installed as a bundle, not in isolation.
Insulation
- Loft insulation (top-up or new);
- Cavity wall insulation;
- Solid wall insulation (internal or external);
- Underfloor insulation;
- Room-in-roof insulation;
- Flat roof insulation.
Heating upgrades
- Replacement of inefficient or broken gas boilers (limited cases);
- First-time central heating systems;
- Air source heat pumps in limited off-gas-grid cases;
- Connection to district heating networks;
- Solar PV (only as part of a whole-home plan).
Controls and what is not funded
- Smart thermostats and heating controls (as add-ons);
- Not funded: double glazing, doors, decorative finishes;
- Not funded: like-for-like boiler swaps unless part of a whole-home plan;
- Not funded: works on homes already at EPC C or above.
The post-works target is usually EPC band D as a minimum, often C, depending on the supplier's strategy and the property's starting point. Homes deeper in fuel poverty (E, F, G) tend to attract the biggest packages because they have the most band uplift to play with.
What goes wrong on the ground
Three traps eligible households fall into
Being eligible is not the same as being installed. These are the failure modes we see most often.
The "free boiler" cold call
If you get an unsolicited call, text, or doorstep visit offering a free boiler under ECO, treat it as a sales pitch first and an offer second. Legitimate ECO works are installed by TrustMark-registered installers using PAS 2035-accredited Retrofit Coordinators. They will not pressure you into signing on the day, they will not ask for a bank transfer, and they will not turn up unannounced. The cold-callers are mostly lead generators selling your details on; some are running outright scams.
Genuine ECO installers will agree to be checked against the TrustMark register at trustmark.org.uk before you sign anything.
Eligibility without delivery
Tens of thousands of households are technically eligible for ECO4 but cannot find an installer with capacity. The reasons: solid wall insulation is labour-intensive and the supply chain is thin; heat pump engineers are in short supply; in dense urban areas planning rules slow external wall insulation to a crawl. The closer the scheme gets to its December 2026 close, the worse this gets, because installers will not start a job they cannot finish.
If a supplier tells you that you qualify but cannot quote a survey date, treat that as a soft "no" and try a second supplier, ECO funding follows the installer's books, not your account.
The December 2026 cliff edge
ECO4 closes 31 December 2026 and the Warm Homes Plan opens in 2027 with a different rulebook. The transition window is the riskiest period in a decade for fuel-poor households. If your application starts in the second half of 2026, you may run out of scheme before you run out of paperwork. The Warm Homes Plan will not simply pick up where ECO4 left off, different eligibility, different measure mix, different installer panels.
Practical rule: apply now if you qualify. Waiting for the Warm Homes Plan is a six- to twelve-month gap with no support route in between.
From cross-subsidy to grants, why the model is changing
ECO is the last large-scale UK retrofit programme paid for by every bill-payer. For fifteen years, the idea was that every household with an energy bill quietly funds works for a few fuel-poor homes a year. That model is now being abandoned, and the Government's reasoning is worth reading carefully:
- ▸Cross-subsidy via standing charges hits low users (often the same vulnerable households) hardest. The 2026 standing-charge reform is a partial fix, but the structural problem is the funding route itself.
- ▸Supplier-led delivery means installer capacity follows supplier targets, not household need. Areas with a thin installer base get neglected even where eligibility is high.
- ▸The Warm Homes Plan moves the cost onto general taxation (~£15bn over the spending review). That makes the policy lever public, visible and debatable, which it has not really been under ECO.
Translation: if you qualify under ECO4 now, the route is faster and the package is more generous than what is likely to replace it. The transition will not be smooth, apply on this side of December 2026 if you can.
Full eligibility checklist for ECO4
There are two ways into ECO4. Most households qualify through Core ECO4. The under-used route is LA Flex.
Core ECO4, means-tested benefits
You qualify automatically if you (or your partner) receive any of:
- Pension Credit (Guarantee Credit element);
- Income-based Jobseeker's Allowance (JSA);
- Income-related Employment and Support Allowance (ESA);
- Income Support;
- Universal Credit;
- Housing Benefit;
- Child Benefit, subject to household income thresholds;
- Working Tax Credit or Child Tax Credit, subject to income.
LA Flex, the Local Authority route
Local Authority Flexible Eligibility (LA Flex) is the back door for households who are not on benefits but are clearly fuel-poor or cold-sensitive. Each local authority publishes its own Statement of Intent setting out the criteria it will use. Common LA Flex routes include:
- Household income below a set threshold (often around £31,000, varies by council);
- A resident with a health condition made worse by cold (respiratory, cardiovascular, mental health);
- An older resident living alone in a poorly insulated home;
- Receipt of a disability benefit (PIP, Attendance Allowance, DLA).
If your council issues a Statement of Intent declaration in your name, you are ECO4-eligible even without being on a means-tested benefit. The catch is that you have to know to ask, most councils do not advertise this route prominently, and most installers will not tell you about it unless you bring it up.
What to actually do
What to do now, depending on your situation
Six routes, each suited to a specific case. Pick the one that matches yours.
Check ECO4 eligibility now, not later
Contact any ECO-participating supplier, you do not have to be their customer to apply. Ask for a survey. If they cannot quote a survey date inside 8 weeks, try a second supplier. The closer to December, the tighter capacity gets.
Don't take cold calls
Any unsolicited "free boiler" call is a sales pitch. Never sign on the day. Verify installers at trustmark.org.uk and report scams to Action Fraud.
If your boiler has died
ECO4 rarely funds a like-for-like swap. If you are replacing a working gas boiler, look at the Boiler Upgrade Scheme for a £7,500 grant towards an air source heat pump. If you are stuck in an emergency, your supplier's hardship fund may help in the meantime.
Off-gas-grid, low-income
The Warm Homes Local Grant, delivered by local authorities, funds energy-efficiency works specifically for low-income households not on the gas grid. Different application route, start with your council, not your energy supplier.
Not on benefits, EPC D to G
Try GBIS for a single insulation measure. No income test for the General Group, only an EPC and council tax band test. Apply before 31 March 2026.
Borderline case
Ask your local authority about LA Flex. If you have a relevant health condition or low income, the council may declare you eligible even without a means-tested benefit. Worth a phone call.
Other UK energy and fuel-poverty schemes alongside ECO4
ECO4 rarely stands alone. Households eligible for ECO are usually eligible for several of the schemes below.
| Scheme | What it pays | How to get it |
|---|---|---|
| Warm Home Discount | £150 one-off rebate on your winter electricity bill | Automatic in England and Wales if on qualifying benefits |
| Pension Credit | Tops weekly income to £238 (single) / £363.25 (couple) | Apply via gov.uk/pension-credit; gateway to multiple schemes |
| Boiler Upgrade Scheme | £7,500 grant towards an air source heat pump | Apply via your MCS-certified installer at gov.uk/apply-boiler-upgrade-scheme |
| Warm Homes Local Grant | Energy-efficiency works for off-gas-grid low-income homes | Delivered by local authorities; criteria vary by council |
| Priority Services Register | Free practical support for vulnerable energy customers | Apply through your supplier and your network operator |
| Smart Export Guarantee | Payment for electricity exported from your solar PV | Apply via your electricity supplier; rates vary by supplier |
Energy Company Obligation, frequently asked questions
Bottom line
Why the next seven months matter more than the next seven years
ECO4 is the last of a generation of UK energy-efficiency schemes funded through everyone's bill. Between now and 31 December 2026 it is still the most direct route to free or part-funded insulation, heating upgrades and (occasionally) boiler replacements for low-income households. From 2027 the Warm Homes Plan takes over, better funded on paper, but new, untested, and with eligibility rules that have not yet been finalised. The transition gap is real.
If you think you might qualify under ECO4 or GBIS, the practical answer is to apply now rather than wait. A surveyed, approved application in 2026 is worth far more than a perfect-on-paper application in 2027 that has nowhere to land.
Think you might qualify?
Check the official Ofgem ECO guidance or compare suppliers running the scheme before December 2026.
More UK energy scheme guides
The services and products mentioned on this website may only represent a small selection of the options available to you. Selectra encourages you to carry out your own research and seek advice if necessary before making any decisions. We may receive commission from selected partner providers on sales of some products and/or services mentioned within this website. Our website is free to use, and the commission we receive does not affect our opinion or the information we provide.