Heat Pump Cost for a 4-Bedroom House: Full 2026 Breakdown
An air source heat pump for a 4-bed detached house costs £11,000 to £16,000 installed. The £7,500 BUS grant reduces your out-of-pocket cost to £3,500 to £8,500. Including radiator upgrades and a hot water cylinder, the realistic total is £6,500 to £14,000 after the grant. Annual running costs are £993 on a heat pump tariff, saving £359 versus gas. This guide covers every cost element specific to 4-bed homes.
Complete cost breakdown
| Cost element | Range | Notes |
|---|---|---|
| Heat pump unit and installation | £11,000 to £16,000 | 10 to 14 kW air source. Includes unit, pipework, controls, MCS certificate |
| BUS grant | -£7,500 | Deducted from installer invoice |
| Net heat pump cost | £3,500 to £8,500 | What you actually pay |
| Radiator upgrades | £3,000 to £5,500 | 4 to 7 radiators typically need upsizing. See radiator sizing guide |
| Hot water cylinder | £800 to £1,500 | Required if replacing a combi boiler |
| Pipework modifications | £0 to £1,500 | If existing pipework is incompatible |
| Concrete plinth | £200 to £500 | Base for outdoor unit |
| Total out of pocket | £6,500 to £14,500 | After BUS grant, including all ancillary costs |
0% VAT applies until March 2027. Costs from MCS installer market data and Energy Saving Trust.
Use our heat pump calculator for a personalised estimate.
What size heat pump for a 4-bed house
A 4-bed detached house typically needs a 10 to 14 kW air source heat pump. The exact size depends on your insulation level.
| Insulation level | Heat demand (kWh) | HP size | Installed cost |
|---|---|---|---|
| Well insulated (270mm loft, filled cavity, double glazed) | 14,000 to 16,000 | 10 to 12 kW | £11,000 to £13,000 |
| Partially insulated | 17,000 to 20,000 | 12 to 14 kW | £13,000 to £15,000 |
| Poorly insulated | 22,000 to 28,000 | 14 to 18 kW | £15,000 to £19,000 |
Insulating first reduces heat pump size and cost. See loft insulation and cavity wall insulation guides.
Insulate first to save £2,000 to £4,000
Loft insulation (£300 to £600) and cavity wall insulation (£400 to £1,500) reduce your heat pump cost and running costs permanently. If you qualify for ECO4, get free insulation first.
Running costs: 4-bed detached
| Heating system | Annual cost | Saving vs gas |
|---|---|---|
| Gas boiler | £1,352 | Baseline |
| Heat pump (standard tariff) | £1,521 | -£169 (more expensive) |
| Heat pump (HP tariff) | £993 | £359 saving |
| Oil boiler | £1,400 to £1,800 | n/a |
| Electric boiler | £4,410 | n/a |
Gas at 6.76p/kWh. HP COP 2.9. 18,000 kWh heat demand. Ofgem Q1 2026 rates.
The tariff makes or breaks the economics. On a heat pump tariff, you save £359/yr versus gas. Over 20 years, that is £7,180. Read our running costs guide for the full comparison. For electric boiler homes, see our electric boiler vs heat pump guide for the dramatic savings.
Ground source vs air source for a 4-bed
| System | Installed cost | After grant | Annual running cost |
|---|---|---|---|
| Air source | £11,000 to £16,000 | £3,500 to £8,500 | £993 (HP tariff) |
| Ground source | £22,000 to £35,000 | £14,500 to £27,500 | £780 (HP tariff) |
Ground source needs 100m+ borehole or 200+ sqm garden. Both qualify for £7,500 BUS grant.
For most 4-bed homes, air source is the practical choice. Ground source saves roughly £200/yr but costs £10,000+ more upfront. Read our costs by house type guide for the full comparison across all property types.
Reduce noise with anti-vibration pads. Manage your system with a smart thermostat. Track costs with an energy monitor.
Frequently asked questions
How much does a heat pump cost for a 4-bedroom house?
£11,000 to £16,000 installed. £3,500 to £8,500 after the £7,500 BUS grant. Total with radiators: £6,500 to £14,500.
What size heat pump does a 4-bed house need?
10 to 14 kW. Insulate first to reduce size and cost.
How much does it cost to run?
£993/yr on a heat pump tariff. £1,521 on standard. See our running costs guide.
Data sources
Costs from Energy Saving Trust. Energy prices from Ofgem Q1 2026. BUS grant from GOV.UK.