ASHP installation costs explained
An air source heat pump installation is a package of several separate costs, not just the price of the outdoor unit. This guide breaks the total down into its parts — the heat pump itself, the hot water cylinder, controls, and radiator upgrades — using typical figures reported by UK installer cost guides, so you know roughly what to expect before getting quotes.
Typical total cost, by property size
These are supply-and-install totals for a straightforward air-to-water ASHP replacing a fossil-fuel boiler, before and after the current £7,500 Boiler Upgrade Scheme (BUS) grant in England and Wales. Actual costs depend heavily on your property's insulation, existing pipework, and how many radiators need upgrading — treat these as a starting point, not a quote.
Figures are indicative UK averages compiled from installer cost guides (Checkatrade, The Eco Experts, MyJobQuote), current as of 2026. Individual quotes commonly range £7,000–£16,000 depending on the factors below — always get several quotes from MCS-certified installers.
What makes up the cost
A quote is really several line items bundled together. Here is roughly what each one costs on its own.
The outdoor unit (and, for split systems, the indoor hydraulic box) is priced mainly by capacity. Larger, higher-output, or high-temperature/R290 models sit at the top of each band.
Fitting the unit, connecting pipework, commissioning and the heat-loss survey typically adds £3,000–£7,000: around £3,000–£4,500 for a standard swap onto existing pipework, rising to £4,500–£7,000 where significant pipework changes are needed.
Most ASHP installs need a new (or first-time) unvented hot water cylinder, since heat pumps heat water more gradually than a combi boiler. A heat-pump-ready cylinder — with a larger heat-exchanger coil to transfer heat efficiently at a lower flow temperature — supplied and fitted typically costs £900–£2,000, depending on size (commonly 150–300 litres for a household) and coil specification. It must be fitted by a G3-registered installer and serviced annually.
A basic room thermostat and outdoor sensor for weather compensation is usually bundled with the unit. Extra controls — additional zone thermostats, smart thermostatic radiator valves, or a multi-zone control setup — typically add £300–£1,200 depending on how many zones and rooms are covered.
Because a heat pump runs at a lower flow temperature than a gas boiler, each radiator gives out less heat for the same size, so some radiators sized for a 70–80°C boiler need replacing with larger ones to keep rooms warm at 35–45°C. Installers typically charge £300–£500 per radiator supplied and fitted — for example, upgrading 10 radiators is commonly quoted around £3,000 in total. Not every radiator needs replacing; a heat-loss survey identifies which ones are undersized for low-temperature operation.
Many properties need a consumer unit upgrade or a new dedicated circuit to the outdoor unit, typically £500–£800. Whether this is needed depends on your existing electrics and the unit's power draw — your installer will confirm this during the survey.
Ongoing running costs are separate from installation — budget roughly £150–£300 for an annual service. Figures above are indicative UK 2026 averages from Checkatrade, The Eco Experts and similar installer cost guides, not fixed prices — always get itemised quotes from at least three installers.
What affects your price
- Property size and heat loss. A bigger or less-insulated home needs a larger, costlier unit — and a properly sized system depends on a room-by-room heat-loss calculation, not a rule of thumb.
- How many radiators need upgrading. A well-insulated home with already-generous radiators may need none; an older, poorly insulated one may need most of them replaced.
- Underfloor heating vs radiators. Underfloor heating suits low flow temperatures perfectly but is expensive to retrofit; sticking with upgraded radiators is usually cheaper for an existing home.
- Existing pipework and cylinder. Reusing existing pipe runs and pipework diameter keeps labour down; microbore pipework or no existing cylinder adds cost.
- Brand and specification. Premium brands, R290 high-temperature models, and longer warranties typically cost more than budget or standard-temperature units.
- Site access and complexity. Where the outdoor unit goes, how far pipework has to run, and any scaffolding or difficult access all affect labour cost.
The government's Boiler Upgrade Scheme currently provides £7,500 towards an air source or ground source heat pump in England and Wales (£2,500 for air-to-air, £5,000 for biomass boilers). It is applied as an upfront discount by your MCS-certified installer — you do not pay the full amount and claim it back.
- Requires an MCS-certified installer and product, and generally a valid EPC with no outstanding loft/cavity wall insulation recommendations.
- Covers new-build replacements of an existing fossil-fuel or heat pump system, not new-build properties.
- Scotland and Northern Ireland have separate schemes — see Home Energy Scotland or your local grants.
- Read our full Boiler Upgrade Scheme FAQ or the official GOV.UK guidance for the current eligibility rules and how to apply.
Related reading
- What is the Boiler Upgrade Scheme? — grant amounts, eligibility, and how to apply
- How do I size a heat pump for my property? — why sizing drives both performance and cost
- ASHP vs GSHP vs WSHP — which is right for my project? — how installed costs compare across heat pump types
- Flow temperature & efficiency — why radiator sizing matters so much for running costs
- Understanding COP & SCOP — how to compare running-cost efficiency between models
Reviewed July 2026. Costs are general UK guide prices, not quotes, and change over time; always confirm current grant eligibility and get itemised quotes from MCS-certified installers before budgeting. This guide is general information, not financial or professional advice.