Air-source heat pumps UK: the honest 2026 buyer's guide
Costs, running costs vs gas, BUS grant, ASHP vs GSHP, and the 10 questions to ask before signing. ~14 min read.
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Heat pumps
A heat pump is essentially
A heat pump is essentially
a fridge running backwards.
It's not magic — it's good physics. Here's what to know before you spend £10,000+ on a new heating system.
The four things to check first
Before any installer turns up at your house, run these checks. They'll save you a lot of wasted Saturdays.
1. Your home's heat loss
A heat pump works best in a well-insulated home. Loft insulation, cavity wall, draught-proofing — these matter more than the kit itself. A good installer will do a room-by-room heat loss survey, not a sales pitch.
2. Radiator size
Heat pumps run cooler water than gas boilers, so radiators often need to be larger. Some can stay; some can't. Underfloor heating is ideal but not required.
3. Outdoor unit space
You need space outside for the ASHP unit — typically beside a wall, on a flat base, with airflow. Not all terraced houses can accommodate one without planning consideration.
4. Hot water cylinder space
If you're on a combi boiler, you'll need a cylinder — typically in an airing cupboard or loft. Plan the space before you sign anything.
Grant
The Boiler Upgrade Scheme (BUS): £7,500 off, explained
The UK government will pay you £7,500 towards an air-source heat pump installation. Here's how it actually works.
Who qualifies
England & Wales homeowners replacing a fossil-fuel boiler (gas, oil, LPG) with an air-source or ground-source heat pump. New-builds don't qualify.
How you claim it
Your MCS-certified installer applies on your behalf and deducts the £7,500 from your quote. You don't apply directly.
What it doesn't cover
The grant covers the heat pump itself — not new radiators, hot water cylinders or extensive insulation work. Make sure the quote splits these out.
Scotland & Northern Ireland: BUS only applies to England & Wales. If you're in Scotland, look at the Home Energy Scotland Grant and Loan. Northern Ireland has separate Renewable Heat support — different scheme, different paperwork.
Read more in this hub
Heat pump suitability by UK house type
Victorian terrace, 1930s semi, post-war estate, 80s build, new-build. What changes — and the single variable that matters more than your house's age.
See by house typeThe Boiler Upgrade Scheme, in full
Who qualifies, the EPC trap that catches people, what BUS doesn't cover, and how the application actually works.
BUS grant guideGet up to 3 quotes from MCS-certified heat pump installers
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