Energies
Air Source Heat Pumps UK — Costs, Grants, and Running Costs in 2026
How much does an air source heat pump cost? What grants are available, how much will you save on energy bills, and is a heat pump right for your home?
Air source heat pumps are one of the leading alternatives to gas boilers. With government grants covering a significant portion of the cost and gas boilers due to be phased out in new-build homes, understanding heat pumps is increasingly important. This guide covers the real costs, available grants, running costs, and whether a heat pump suits your home.
How Air Source Heat Pumps Work
An air source heat pump extracts heat from the outside air — even in cold weather — and uses it to heat your home and hot water. It works like a refrigerator in reverse.
| Component |
Purpose |
| Outdoor unit |
Extracts heat from the air using a fan and refrigerant |
| Compressor |
Compresses the refrigerant to increase its temperature |
| Heat exchanger |
Transfers heat to your central heating system |
| Indoor unit / cylinder |
Heats your water and distributes warmth |
| Term |
What it means |
| COP (Coefficient of Performance) |
The ratio of heat output to electricity input |
| Typical COP |
2.5–3.5 (meaning 1kW of electricity produces 2.5–3.5kW of heat) |
| Seasonal COP (SCOP) |
Average COP across the whole year, accounting for winter drops |
A COP of 3.0 means for every £1 of electricity you put in, you get £3 worth of heating. This is why heat pumps are more efficient than gas boilers (which operate at 85–95% efficiency at best).
How Much Does an Air Source Heat Pump Cost?
Installation Costs (Before Grant)
| Home size |
Heat pump size |
Typical installed cost |
| Small (1–2 bed flat/house) |
5–7 kW |
£7,000 – £10,000 |
| Medium (3 bed semi) |
8–12 kW |
£9,000 – £13,000 |
| Large (4+ bed detached) |
12–16 kW |
£12,000 – £18,000 |
What Is Included
| Item |
Typical cost |
| Heat pump unit |
£3,000 – £7,000 |
| Installation labour |
£2,000 – £4,000 |
| Hot water cylinder |
£500 – £1,500 |
| Pipework and connections |
£500 – £2,000 |
| Controls and thermostat |
£200 – £500 |
| Commissioning |
Included in installation |
Additional Costs You May Need
| Extra |
Typical cost |
When needed |
| Larger radiators |
£2,000 – £4,000 |
If existing radiators are too small for heat pump temperatures |
| Underfloor heating |
£3,000 – £8,000 |
Ideal partner for heat pumps but not always required |
| Loft and wall insulation |
£1,000 – £5,000 |
Essential for heat pump efficiency |
| Electrical upgrade |
£500 – £1,500 |
If your consumer unit or supply needs upgrading |
| Radiator upgrades |
£150 – £300 per room |
Replacing small radiators with larger ones |
Cost After the Boiler Upgrade Scheme Grant
| Scenario |
Installed cost |
Grant |
Net cost |
| Small home |
£8,000 |
£7,500 |
£500 |
| Average home |
£11,000 |
£7,500 |
£3,500 |
| Large home |
£15,000 |
£7,500 |
£7,500 |
| Average + new radiators |
£14,000 |
£7,500 |
£6,500 |
Grants and Financial Support
Boiler Upgrade Scheme (BUS) — England and Wales
| Detail |
Information |
| Grant amount |
£7,500 for air source heat pumps |
| Where |
England and Wales |
| Eligibility |
Homeowner (not new build), valid EPC, MCS-certified installer |
| How it works |
Grant is paid to the installer, who deducts it from your bill |
| Deadline |
Currently available — check for scheme extensions |
| Multiple grants |
One per property |
You must use an MCS-certified installer to qualify. The installer handles the grant application — you sign a voucher and the grant is deducted from the cost. You do not receive cash.
Scotland — Home Energy Scotland
| Detail |
Information |
| Grant |
Up to £7,500 (or £9,000 in rural/island areas) |
| Loan |
Interest-free loan of up to £7,500 |
| Combined |
Up to £15,000+ of support |
| Contact |
Home Energy Scotland on 0808 808 2282 |
Other Support
| Scheme |
Details |
| ECO4 |
Free or subsidised heat pump for eligible low-income households |
| 0% VAT |
No VAT on heat pump installations (energy-saving materials) |
| Local authority grants |
Some councils offer additional support — check your council |
Running Costs Compared
Annual Heating Costs
| Heating system |
Efficiency |
Fuel cost per kWh |
Annual cost (average 3-bed home) |
| Gas boiler (modern) |
90% |
~7p (gas) |
£850 – £1,100 |
| Oil boiler |
85% |
~8p (oil) |
£1,000 – £1,400 |
| Electric storage heaters |
100% |
~24p (electricity) |
£2,000 – £2,800 |
| Air source heat pump |
COP 3.0 |
~8p effective (24p ÷ 3) |
£700 – £1,000 |
| Heat pump + TOU tariff |
COP 3.0 |
~5p effective |
£450 – £700 |
Key insight: Although electricity costs roughly 3–4 times more per unit than gas, a heat pump’s efficiency (COP of 3.0+) means the effective cost per unit of heat delivered is comparable. With a time-of-use (TOU) tariff that offers cheap overnight electricity, heat pumps can be significantly cheaper.
Savings Compared to Other Systems
| Replacing |
Typical annual saving |
| Old gas boiler (70% efficient) |
£200 – £500 |
| Modern gas boiler (90% efficient) |
£0 – £200 |
| Oil boiler |
£200 – £600 |
| LPG boiler |
£400 – £800 |
| Electric storage heaters |
£800 – £1,500 |
| Direct electric heating |
£1,000 – £2,000 |
Heat pumps save the most money when replacing electric heating, oil, or LPG. Savings versus a modern gas boiler are smaller and depend heavily on tariff rates.
Maximising Savings
| Strategy |
Impact |
| Switch to a time-of-use electricity tariff |
Run the heat pump overnight at 5–10p/kWh instead of 24p |
| Add solar panels |
Generate free electricity to run the heat pump |
| Improve insulation |
The less heat you lose, the less the heat pump needs to produce |
| Use weather compensation controls |
The system adjusts output based on outside temperature |
| Keep the heat pump running at steady, low temperatures |
More efficient than cycling on and off at high temperatures |
Is Your Home Suitable?
Ideal Conditions
| Factor |
Ideal |
Possible with upgrades |
| Insulation |
Well-insulated (loft, walls, floors) |
Can improve insulation first |
| Radiators |
Large enough for low-temperature operation (45–50°C) |
Can upgrade radiators |
| Outdoor space |
Room for the outdoor unit (about the size of a washing machine) |
Most gardens accommodate this |
| Hot water |
Space for a hot water cylinder |
If you currently have a combi boiler, you will need to add a cylinder |
| Electrical supply |
Single-phase OK for most domestic units |
Three-phase rarely needed |
Homes Where Heat Pumps Work Best
| Property type |
Suitability |
| Well-insulated modern home |
Excellent — may need no upgrades |
| Detached house with garden |
Excellent — plenty of space |
| Semi-detached house |
Good — check noise distance from neighbours |
| Older house with cavity walls |
Good, if walls and loft are insulated |
| Solid-wall older home |
Can work but may need external wall insulation |
| Flat or terraced house |
Possible but space for outdoor unit and noise may be issues |
Homes Where Heat Pumps Are More Challenging
| Situation |
Challenge |
| Very poorly insulated |
Heat demand too high — insulate first |
| No space for outdoor unit |
The unit needs airflow and a solid base |
| Noise-sensitive location |
The outdoor unit produces some noise (similar to a fridge) |
| Listed building |
Planning permission may be needed |
| Very large, draughty house |
May need a large, expensive system |
Planning Permission
| Situation |
Permission needed? |
| Detached house |
No (permitted development) |
| Semi-detached house |
No (if noise rules met) |
| Terraced house |
No (if noise and distance rules met) |
| Flat |
Usually yes |
| Listed building |
Yes |
| Conservation area |
Possibly — check with council |
| Noise limits |
Must not exceed 42dB at nearest neighbour’s window |
Heat Pumps vs Gas Boilers
| Factor |
Air Source Heat Pump |
Gas Boiler |
| Upfront cost |
£8,000 – £15,000 (before grant) |
£2,000 – £4,000 |
| Running cost |
£700 – £1,000/year |
£850 – £1,100/year |
| Efficiency |
250–350% (COP 2.5–3.5) |
85–95% |
| Lifespan |
20–25 years |
10–15 years |
| Maintenance |
Annual service £100–£200 |
Annual service £60–£120 |
| Carbon emissions |
Low (zero if using renewable electricity) |
Significant |
| Government support |
£7,500 BUS grant |
None |
| Future-proofing |
Gas boiler ban in new builds approaching |
Will need replacing |
| Heating delivery |
Best with large radiators or underfloor heating |
Works with any radiators |
| Hot water |
Needs a cylinder |
Combi boilers heat on demand |
How to Get an Air Source Heat Pump
Step by Step
| Step |
Action |
| 1 |
Check your home’s insulation — improve if needed |
| 2 |
Get a current EPC (required for the BUS grant) |
| 3 |
Get quotes from at least 3 MCS-certified installers |
| 4 |
Installer designs the system and sizes it for your home |
| 5 |
Installer applies for the BUS grant on your behalf |
| 6 |
Grant is approved (usually within days) |
| 7 |
Installation takes 2–5 days |
| 8 |
System is commissioned and you are shown how to use it |
Choosing an Installer
| What to check |
Why |
| MCS certification |
Required for the BUS grant and a mark of quality |
| At least 3 quotes |
Prices vary significantly between installers |
| References |
Ask to speak to previous customers |
| System design |
A proper heat loss calculation should be done for your home |
| Warranty |
Look for 5–10 year warranties on the unit |
| Aftercare |
Annual servicing should be offered |
Red Flags
- No MCS certification
- No heat loss survey before quoting
- Oversized or undersized system for your home
- Pressure to commit without comparing quotes
- No mention of potential radiator or insulation upgrades
Maintenance
| Task |
Frequency |
Cost |
| Annual service |
Every year |
£100 – £200 |
| Filter cleaning |
Every 6 months |
DIY |
| Check refrigerant levels |
During annual service |
Included |
| Clear debris from outdoor unit |
Regularly |
DIY |
| Check defrost cycle works |
Winter |
DIY |
Heat pumps have fewer mechanical parts than gas boilers and generally require less maintenance. The outdoor unit should be kept clear of leaves, snow, and debris.
Summary
| Key point |
Details |
| Typical cost installed |
£8,000 – £15,000 |
| BUS grant |
£7,500 (England and Wales) |
| Net cost after grant |
£500 – £7,500 |
| Running cost |
£700 – £1,000/year (similar to gas) |
| Efficiency |
250–350% |
| Lifespan |
20–25 years |
| Best savings vs |
Oil, LPG, or electric heating |
| Planning permission |
Usually not needed |
| VAT |
0% |
Air source heat pumps are a long-term investment that can cut heating bills (especially if replacing oil or electric), reduce your carbon footprint, and future-proof your home against the move away from fossil fuel heating. The £7,500 BUS grant makes the upfront cost much more manageable.
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