Cost guides › Air source heat pump
United Kingdom
Air source heat pump cost
Replacing a gas boiler with an 8 kW air source heat pump typically costs £13,000 with 0% VAT, before any grant, and most quotes fall between £10,100 and £16,800. In England and Wales the Boiler Upgrade Scheme takes £7,500 off when you use an MCS certified installer. A basic monobloc system with a separate cylinder is about £9,750; a zoned system with larger buffer, softener and smart controls is nearer £15,400.
Most homeowners pay
0% VAT on installing energy-saving materials (heat pumps, insulation, solar) until 31 March 2027
Estimate your project
Cost by region
| Location | Basic | Mid-range | Premium |
|---|---|---|---|
| London | £9,950 | £13,200 | £15,700 |
| Scotland | £9,750 | £13,000 | £15,500 |
| East | £9,700 | £12,900 | £15,400 |
| East Midlands | £9,650 | £12,900 | £15,300 |
| North East | £9,650 | £12,900 | £15,300 |
| North West | £9,700 | £12,900 | £15,400 |
| South East | £9,750 | £12,900 | £15,400 |
| South West | £9,650 | £12,900 | £15,300 |
| Wales | £9,650 | £12,900 | £15,300 |
| West Midlands | £9,650 | £12,900 | £15,300 |
Show all regions
| Yorkshire and The Humber | £9,600 | £12,800 | £15,300 |
What's included
Mid-range
- Disconnecting and removing the old boiler, its pipework and flue connections, with the scrap taken away
- A concrete base for the outdoor unit with anti-vibration mounting
- An 8 kW split air-to-water heat pump (R32) with an indoor hydronic unit and built-in hot water tank
- Insulated refrigerant pipes between the outdoor and indoor units, and a condensate drain
- A 50-100 litre buffer tank and insulated flow and return pipework to the existing heating system
- Magnetic filter, heating and hot water expansion vessels and safety valve
- A dedicated electrical supply from the consumer unit with its own RCBO
- A programmable room thermostat
- Filling, venting and commissioning the system
What affects the cost
Heat loss and unit size
The unit is sized from a room-by-room heat loss calculation, not from the old boiler's rating; a combi boiler is often far larger than the house needs. Larger or draughtier homes need a bigger heat pump, which costs more to buy and run.
Radiators and pipework
Heat pumps run at lower flow temperatures than gas boilers, so some radiators may need to be replaced with larger ones and undersized or microbore pipework may need upgrading. This is not included in our figures and is the most common extra on UK quotes.
Space for a hot water cylinder
Most UK homes switching from a combi boiler have no cylinder, so room has to be found for an indoor unit with a hot water tank, often the airing cupboard or a utility space. Relocating it or building a cupboard adds cost.
Outdoor unit position
A short pipe run from a ground-level spot close to the plant room keeps costs down. Long runs, wall brackets, flat roofs or sites needing extra noise attention add labour and materials.
Electrical supply
The heat pump needs a dedicated circuit, and an old consumer unit may need replacing. Electrical work must be done by a registered electrician or notified to building control in England and Wales.
Removing the gas supply
Disconnecting and capping the gas supply to the old boiler is gas work and must be done by a Gas Safe registered engineer. If you are giving up gas altogether, removing the meter is arranged separately and is not included here.
How to save
- Use an MCS certified installer so you can claim the £7,500 Boiler Upgrade Scheme grant in England and Wales, or apply to Home Energy Scotland if you live in Scotland.
- Improve loft and wall insulation and draught-proofing first; a lower heat loss means a smaller unit and fewer radiator upgrades.
- Ask the installer to check which radiators actually need upsizing instead of replacing them all.
- Book before 31 March 2027 while the 0% VAT rate on heat pump installation applies.
Grants, tax and rules
Boiler Upgrade Scheme (England and Wales)
£7,500 off an air source or ground source heat pump. The installer must be MCS certified. Our figures are shown before the grant is deducted.
Scotland
Home Energy Scotland offers a grant of up to £7,500, plus an optional interest-free loan of up to £7,500.
0% VAT until 31 March 2027
Installing a heat pump is charged at 0% VAT until 31 March 2027, and our figures use that rate.
Warm Homes Plan
Published in January 2026, it commits £15bn to 2030, including grants for low-income households and low- or zero-interest loans that are being phased in.
Frequently asked questions
How much does an air source heat pump cost in the UK?
Replacing a gas boiler with an 8 kW air source heat pump costs around £13,000 with 0% VAT, before the £7,500 Boiler Upgrade Scheme grant in England and Wales. Radiator upgrades, if needed, are extra.
Who can get the Boiler Upgrade Scheme grant?
The scheme covers homes in England and Wales and gives £7,500 off an air source or ground source heat pump. The installer must be MCS certified, so check certification before you sign. In Scotland, Home Energy Scotland offers a grant of up to £7,500 plus an optional interest-free loan.
Can a heat pump replace a combi boiler?
Yes, but a heat pump does not heat water on demand like a combi, so you need a hot water cylinder or an indoor unit with a built-in tank. Plan where it will go before choosing an installer.
Will I need new radiators with a heat pump?
Often some, not all. Because a heat pump runs at a lower flow temperature, rooms with small radiators may need larger ones to stay warm. The installer's heat loss survey should list each room and say which radiators need changing.
Does a heat pump work in an old solid-wall house?
It can, but solid-wall houses lose more heat, which means a larger unit and more radiator work. Insulating walls and the loft first lowers both the installation cost and the running cost.
How long does it take to install a heat pump?
The installation itself usually takes two to five days, with a day or so without heating while the old boiler is removed and the system is connected. Radiator changes and a new cylinder cupboard add time.
How this estimate is calculated
Work hours: 49.6 · Labour: £2,066 · Materials: £10,885
Sources: ONS Annual Survey of Hours and Earnings, tables 14 and 15; Regione Toscana, Prezzario dei Lavori 2026 (CC BY 4.0); ECB exchange rates.