Homes with back boilers and ECO4: questions UK households ask (guide 2026)

Guide by ApplyFreeBoiler.uk (Reliant Energy Solutions Ltd), a heating and insulation installer in Bury, Greater Manchester. We are not the government, Ofgem or an energy supplier.

Some older UK homes still have a back boiler, a boiler fitted behind a gas fire in the living room fireplace, which heats the radiators and a hot water cylinder. Back boilers are often decades old, which raises a few common questions when a home is assessed for an ECO4 heating upgrade. This guide covers questions households commonly ask. It is general information from ApplyFreeBoiler.uk, a heating and insulation installer in Bury. What is recommended depends on the survey and the scheme rules at the time. This page does not guarantee funding.

1. Say you have a back boiler

Tell the surveyor the boiler sits behind a fire, and whether the fire in front still works.

2. The fire and fireplace

Say whether you want to keep a fire in that fireplace, as removing a back boiler can affect the fire and chimney.

3. Hot water cylinder

Mention where your hot water cylinder is, usually in an airing cupboard, and whether you use an immersion heater.

4. Tanks in the loft

Say whether there are cold water or expansion tanks in the loft.

5. Radiators

Point out radiators that stay cold, leak or are much older than the rest.

6. Where a new boiler could go

Think about where a new boiler might sit, such as a kitchen wall or cupboard, and mention any space you already have in mind.

7. Clear access

Clear space around the fire, airing cupboard, meters and loft hatch before the survey visit.

8. Check funding and local figures

See ECO measures by council on ApplyFreeBoiler.uk, built from DESNZ Household Energy Efficiency statistics, to see how many ECO measures have been installed in your local authority area. Use the ApplyFreeBoiler.uk eligibility check to see whether an ECO4 heating or insulation pathway may be available for your home in England, Scotland or Wales. ECO4 is due to close on 31 December 2026.