Why “non-condensing” matters for ECO4
ECO4 does not fund a new boiler simply because a household would like one. It funds measures that improve a home’s energy rating, and for boilers the key word is non-condensing.
The law behind ECO4 defines an inefficient heating system as a central heating system that includes a non-condensing boiler. Ofgem then explains what that means for households: heating system upgrades can only happen when the existing boiler is non-condensing, and those upgrades are not capped.
That leaves three cases:
| Your boiler | Can ECO4 replace it? |
|---|---|
| Non-condensing, working or broken | Yes, as an upgrade, for a qualifying homeowner. Not capped |
| Condensing, broken and cannot be economically repaired | Possibly, but Ofgem caps how many of these suppliers fund |
| Condensing and working | Unlikely |
| No boiler or central heating at all | Yes, as first-time central heating |
Is my boiler non-condensing? Four checks
- Look for a condensate pipe. Condensing boilers produce water, which drains away through a small plastic pipe, usually white or grey, from the bottom of the boiler to a drain or an outside gully. No pipe usually means non-condensing.
- Check the age. Building Regulations standards changed in 2005, so most gas boilers fitted in England and Wales since then are condensing. If yours was fitted before then, it is probably non-condensing.
- Look for a pilot light. A small flame that you can see burning all the time is a sign of an older boiler.
- Check the model. The make and model are usually on the front panel or under the cover. The manual, or the manufacturer, will confirm whether it is condensing.
Back boilers count too
A back boiler, fitted behind a gas fire in the fireplace, is usually non-condensing. See our guide to back boiler replacement grants.
Combi, system or regular: all can qualify
The boiler type does not decide eligibility. What matters is whether it is non-condensing.
- Combi boiler: heats radiators and gives hot water on demand, with no cylinder. Older combis from before about 2005 are often non-condensing.
- System boiler: heats radiators and a hot water cylinder, with the pump built in.
- Regular, or heat-only, boiler: works with a hot water cylinder and usually tanks in the loft.
When an old boiler is upgraded, the installer may suggest a different type, for example a combi in place of a regular boiler and cylinder. That depends on your water pressure and how much hot water you use at once.
Who qualifies for an ECO4 boiler upgrade
Set by the scheme · Ofgem and GOV.UK
What ECO4 looks for
- Someone in the household receives a qualifying means-tested benefit, such as Universal Credit, Pension Credit or Housing Benefit, or the council declares the household eligible through ECO4 Flex.
- You own the home and live in it. ECO4 does not fund boiler work in rented homes.
- The home has an energy rating (EPC) of D to G.
- The boiler is non-condensing.
- Insulation is installed first where the home needs it, and the project lifts the home’s rating enough.
Our service · not a scheme rule
How Warm Home Support handles your enquiry
These describe how we look at an enquiry. They are not ECO4 requirements, and they do not change what the scheme itself allows.
- We help you check the household, the home and the boiler before you contact an installer.
- If ECO4 does not fit, we point you to the scheme that does.
The insulation rule is set out in the ECO4 delivery guidance: a home rated E to G normally needs its exterior cavity walls and loft insulated before any heating is installed, and a home rated D needs at least one insulation measure first. The project has to lift a home rated D or E to at least band C, and a home rated F or G to at least band D.
Tenants
ECO4 does not fund the replacement, upgrade or repair of a boiler in a rented home, private or social. If you rent and the boiler is old or unreliable, raise it with your landlord.
What the upgrade involves
A like-for-like swap of a non-condensing boiler is usually straightforward, but a few things often change:
- A new flue. Condensing boilers produce a visible plume of vapour, so the flue position may move.
- A condensate pipe to a drain, which needs protecting from frost if it runs outside.
- A system clean. The radiators and pipework are cleaned, and a filter is often fitted, to protect the new boiler.
- New controls, such as a programmer and room thermostat.
- Possibly a new boiler type, such as a combi in place of a system with a cylinder.
A replaced or upgraded boiler under ECO4 must come with a warranty of at least two years.
Old boiler? Check what applies
Tell us how your home is heated and whether you own it. We will take you to our eligibility check with those answers filled in. It is free, and nothing is sent until you choose to send it.
Timing
ECO4 ends on 31 December 2026, and the work has to be finished by then. If the project needs insulation first, allow for that as well. Our step-by-step guide to applying for an ECO4 boiler grant explains what happens at each stage.
If you do not qualify
- Pensioners: see free boiler grants for pensioners.
- Not on benefits: see boiler grants if you are not on benefits.
- Open to a heat pump: the Boiler Upgrade Scheme gives homeowners in England and Wales a grant towards a heat pump, with no income test.
- Paying yourself: our boiler replacement page explains what a quote should include.
