Heat pumps are one of the biggest changes in home heating in decades – but they’re still unfamiliar to many homeowners.
This concise guide explains the basics of air source heat pumps, when they work well, and how they fit into your EPC and home‑upgrade plan.
For a detailed cost breakdown, see Air Source Heat Pump Costs UK (2025 Guide). To compare boilers and heat pumps, read Boiler vs Heat Pump: Costs, Savings & Which Is Right for You.
How heat pumps work (in one minute)
An air source heat pump:
- Takes low‑grade heat from the outside air.
- Uses electricity and a refrigerant circuit to boost that heat.
- Delivers it into your home via radiators or underfloor heating, and often heats a hot water cylinder.
Instead of burning fuel, it moves heat – which is why it can deliver 2.5–3.5 units of heat for every unit of electricity used in a well‑designed system.
When heat pumps work best
They’re at their strongest when:
- Your home is well insulated (loft, walls, floors) and relatively draught‑free.
- Radiators are sized for lower flow temperatures, or you have underfloor heating.
- You’re comfortable with steady background warmth rather than sharp on/off cycles.
If your home is very leaky or still has major insulation gaps, tackle those first – see 27 Ways to Improve Your EPC Rating and Cheapest Ways to Improve Your EPC Rating.
EPC and carbon benefits
From an EPC perspective, heat pumps:
- Usually improve your score more than a like‑for‑like new boiler, especially in well‑insulated homes.
- Reduce direct carbon emissions, as there’s no on‑site combustion.
This makes them particularly relevant if you’re aiming for band C or better – see How to Improve EPC from D to C.
Grants and support
Heat pumps can be expensive to install, but the Boiler Upgrade Scheme (BUS) gives a £7,500 grant towards an air or ground source heat pump in England and Wales – confirmed to run to 2029/30. A separate £2,500 grant is available for air‑to‑air heat pumps. Combined with the wider £13.2bn Warm Homes Plan, that brings real installations well within reach. For funding context, read:
- Home Energy Grants UK 2026: Complete Guide to Funding
- Boiler Grants UK 2026
- Energy Grants Update 2026
Next steps
- Check your current heating and EPC via our EPC checker.
- Improve insulation and draught‑proofing where needed.
- Use the detailed cost and comparison guides above to decide whether a heat pump, a new boiler, or a phased approach is best for your home.