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AnswerWhat size heat pump for a 4-bedroom house?
A typical 4-bedroom house in the UK needs roughly a 9–13 kW air-source heat pump — the exact size depends on your home's heat loss, not floor area alone.
Heat pumps are sized on heat loss, so an MCS installer should run a room-by-room calculation. Use this as a starting point. A same-sized bungalow needs a similar unit; a flat is usually about 20% smaller — the calculator below adjusts for both.
| Estimated size | 9–13 kW |
|---|---|
| Installed cost | £11,000–£15,000 before grant |
| After the £7,500 grant | £3,500–£7,500 |
Heat-pump size calculator → · Check the grant →
2026 figures, based on Energy Saving Trust, Ofgem & gov.uk data · always confirm with a professional survey.