ECO4 is the government scheme that makes large energy suppliers pay for insulation and heating upgrades in the homes that waste the most heat. If you live in a poorly insulated property and you or someone in your household claims a qualifying benefit, the work can be fully funded, with nothing for you to pay. The catch is that the scheme is targeted, the rules are strict, and it is due to close at the end of December 2026, so it pays to understand how it works and whether your home fits.
The short answer. ECO4 funds free energy upgrades (loft and wall insulation, first-time central heating, boiler and heating repairs, sometimes solar or a heat pump) for low-income households in homes rated EPC D to G. Eligibility usually depends on a means-tested benefit, though a council's ECO4 Flex route can widen it. The scheme runs until 31 December 2026 and is funded by the big energy suppliers, not by you.
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What ECO4 actually is
ECO stands for the Energy Company Obligation. It is a legal duty placed on larger energy suppliers to spend money improving the energy efficiency of homes that are hard to heat and occupied by people on low incomes. ECO4 is the fourth phase of that obligation, and it took a noticeably stricter line than earlier versions.
The key difference with ECO4 is the whole-house approach. Rather than fitting one measure in isolation, an installer assesses the property and has to show that the package of work will lift the home's energy rating by a set amount. So instead of just a new boiler, an eligible household might get loft insulation, cavity wall insulation and heating controls together. The aim is to take the worst-performing homes (those rated E, F or G on their Energy Performance Certificate) and pull them up the scale.
The work is paid for by the obligated suppliers. For the household that qualifies, the standard measures are fully funded, with no contribution to find. That is what people mean when they call these "free" upgrades. The cost is recovered across everyone's bills, which is one reason your energy bill carries policy costs baked into the unit rate and the standing charge.
Who qualifies for ECO4
There are two doors into ECO4. The main route is benefits-based, and the second is a council-led flexibility route.
The benefits route
You generally qualify if someone living in the property receives one of the qualifying means-tested benefits and the home is poorly insulated. Commonly accepted benefits include:
- Universal Credit
- Pension Credit (Guarantee or Savings element)
- Income-based Jobseeker's Allowance (JSA) and income-related Employment and Support Allowance (ESA)
- Income Support
- Child Tax Credit and Working Tax Credit
- Housing Benefit
- Child Benefit (subject to an income cap by household size)
- Pension Age and Disability Cost of Living payments in some cases
On top of the benefit, the property usually needs an EPC rating of D or lower for heating measures, and the worst-rated homes (E, F and G) are prioritised. There are extra rules for social housing and for park homes.
The ECO4 Flex route
If no one in the home claims a listed benefit, you may still get in through ECO4 Flex, sometimes called LA Flex. This lets your local council set wider rules for its own area, aimed at households in fuel poverty or vulnerable to cold. Typical triggers are a household income below a council threshold (often around £31,000, though some councils set it higher), being over 65 or having a child under five, or a household member with a health condition made worse by living in a cold home. The council issues a "statement of intent" confirming you meet its criteria, which the installer then uses to claim the funding.
Because every council sets its own Flex threshold and rules, the only reliable way to check is to search for your council's name alongside "LA Flex" or "ECO4 Flex" and read its current statement.
What upgrades ECO4 can cover
ECO4 funds the measures that move a cold, inefficient home up the EPC scale fastest. Exactly what you are offered depends on the survey, the current state of the property and what will deliver the required improvement. Common measures include:
- Loft insulation, including top-ups to the recommended depth
- Cavity wall insulation and solid wall insulation for older properties
- Underfloor and room-in-roof insulation
- First-time central heating for homes that have never had it
- Boiler repairs or replacement where the existing system is broken or very inefficient
- Heating controls such as thermostats and radiator valves
- In some cases solar panels or a heat pump, usually as part of a wider package
ECO4 leans towards insulation first because the cheapest unit of energy is the one you never have to buy. A well-insulated home holds heat longer, so the boiler or heat pump runs less often. Insulation also keeps benefiting you year after year, long after any single bill.
What it could save on your bills
The value of an ECO4 package is two things at once: the upgrade you do not have to pay for, and the running-cost reduction afterwards. The exact saving depends on your home, but the table below gives a sense of scale using current energy rates. These are illustrative figures for a typical older home, not a guarantee for any one property.
| Measure | Typical heat loss it tackles | Rough annual gas saving |
|---|---|---|
| Loft insulation (none to recommended depth) | Heat escaping through the roof | £250 to £400 |
| Cavity wall insulation | Heat lost through unfilled walls | £200 to £350 |
| Solid wall insulation | Heat lost through solid brick walls | £300 to £600 |
| Replacing a broken or very old boiler | Wasted fuel from poor efficiency | £150 to £300 |
Gas savings estimated at 7.97p per kWh, Ofgem cap October to December 2026. Actual savings vary by property size, occupancy and current insulation.
Because most of these savings come from burning less gas, the benefit shows up as a smaller variable charge on your bill. The fixed standing charge does not change, which is worth remembering when you read claims about cutting bills in half. For more on that split, see how the standing charge works.
How to apply, and what to watch for
You do not apply to Ofgem or the government directly. ECO4 is delivered by suppliers and the installers working on their behalf, so the process runs through an installer or your local council's Flex scheme.
- Check eligibility first. Confirm whether anyone in the home claims a qualifying benefit, or look up your council's ECO4 Flex rules if not.
- Find a reputable installer. Work funded under ECO4 must be carried out by a TrustMark-registered installer to PAS standards. Ask for the registration before agreeing to anything.
- Expect a survey. A retrofit assessment of the property is part of the process, since the whole-house rule means the installer has to model the improvement.
- Pay nothing for standard measures. For an eligible household the funded measures should cost you nothing. Be wary of any firm asking for an upfront fee or a deposit for "free" ECO4 work.
A note of caution on cold callers and pushy ads. ECO4 attracts a lot of marketing, and not all of it is honest. Genuine grant funding never needs an upfront payment, and a trustworthy installer will not pressure you into a same-day decision. If a deal sounds too good, check the installer's TrustMark registration and your council's official page before signing.
The bottom line
ECO4 is one of the few schemes that can fully fund real fabric improvements, not just a single gadget, for the households that need them most. If you are on a qualifying benefit (or fit your council's Flex rules) and your home is cold and poorly insulated, it is well worth pursuing, because the upgrades keep paying back through lower heating use for as long as you live there.
The pressing point is timing. ECO4 is due to close on 31 December 2026, the government has confirmed there will be no ECO5 successor obligation, and support after that is expected to shift to council-delivered grants under the Warm Homes Plan. Funding is also allocated as installers claim it, so it can tighten well before the deadline. Schemes, thresholds and end dates do change, so check the current rules and eligibility on the official Ofgem Energy Company Obligation page and GOV.UK before you commit. If ECO4 does not fit, it is worth looking at the Great British Insulation Scheme, the Boiler Upgrade Scheme and the Warm Home Discount as alternatives.