How much does an air source heat pump cost to install in the UK? (2026 guide)
Short answer: around £12,500 on average before any grant, according to the latest government Boiler Upgrade Scheme figures. After the £7,500 BUS grant, most homeowners pay somewhere between £3,500 and £6,000. Some smaller properties pay less. Longer answer: it depends on your house, your insulation, your existing radiators, and what the survey turns up. The headline number is a starting point, not a quote. This guide goes through the real numbers, by property size, by what is and is not included, by what adds cost that most installers do not volunteer upfront. There is a West Midlands section near the end with figures specific to Birmingham, Worcester, and the surrounding towns. 2026 cost summary What you pay by property size System size drives most of the price difference. A small flat needs a 5 kW unit. A large detached house might need 14 or 16 kW. That is not just a bigger box, it is more pipework, longer install time, and a higher unit price. These figures cover the heat pump unit, labour, hot water cylinder, standard pipework, and commissioning. Radiator upgrades, electrical work, and other extras are separate, that list comes next. Property System Cost before grant After £7,500 BUS grant VAT saving (0%) 1 to 2 bed flat/house 5 to 7 kW £7,000 to £10,000 £0 to £2,500 ~£350 to £500 2 to 3 bed semi/terrace 7 to 10 kW £9,000 to £12,500 £1,500 to £5,000 ~£450 to £625 3 to 4 bed detached 10 to 13 kW £11,000 to £15,000 £3,500 to £7,500 ~£550 to £750 4 to 5 bed large property 13 to 16 kW £14,000 to £18,000 £6,500 to £10,500 ~£700 to £900 VAT saving calculated at 0% versus 5% standard rate. Relief confirmed until 31 March 2027. Source: HMRC. What Wunergy’s price includes Every installation covers: What is not in that list depends on the property. Older houses usually need more. The extras that catch people out Comparison websites quote national averages. They do not show you what a surveyor finds when they actually walk around your house. These are the most common additions: What Typical cost When it applies Radiator upgrade (per radiator) £150 to £400 Older or undersized rads New hot water cylinder £400 to £900 No cylinder, or current too small Consumer unit upgrade £500 to £1,000 Old electrics that cannot handle load Scaffolding £300 to £600 Unit needs to go high on a wall Pipework changes £200 to £800 Narrow-bore or complex existing pipework Smart controls/thermostat £150 to £400 Recommended on all installs Annual service £150 to £300/yr Every year, keeps warranty valid Watch this when comparing quotes A quote of £8,000 that excludes three radiator upgrades and a new cylinder is not cheaper than a £9,500 quote that includes them. Always ask what is and is not in the price. Wunergy provides a fully itemised quote after the free survey so nothing comes as a surprise later. Why some jobs cost more than others Insulation and heat loss Before any system gets designed, a heat loss calculation works out how much heat your home bleeds on a cold day. Poor insulation means the number is higher, which means a bigger system. A well-insulated three-bed semi typically needs an 8 kW unit. The same house with no loft insulation and single glazing might need 12 kW. That is a difference of roughly £2,000 to £3,000 in unit cost before labour is touched. Radiators Gas boilers push water at 60 to 70 degrees. Heat pumps run at 35 to 50 degrees. Lower flow temperatures mean older radiators often do not give off enough heat, they were sized for the hotter system. Replacing undersized radiators is one of the most common additional costs. Budget £150 to £400 per radiator. A three-bed house typically has seven to nine. Do that maths before dismissing the upgrade. Existing pipework and electrics Narrow-bore pipework in older properties sometimes needs replacing before a heat pump can circulate water properly. Outdated consumer units occasionally need upgrading to handle the additional load. Neither is guaranteed, but both get flagged during a proper survey. Where the unit goes Most outdoor units go on a wall bracket or a small ground pad. Straightforward. But if the best location for airflow means scaffold access or a longer pipe run through the building, that adds to the job. Brand and spec Wunergy fits Samsung units with an ErP A+++ rating. That is the top efficiency band and a requirement to access the Boiler Upgrade Scheme grant. Budget brands exist. Some perform fine. Some do not. The difference shows up in the bills every winter and in how easy it is to get parts if something needs fixing in year eight. Running costs once it is in Electricity is more expensive per unit than gas. That is just the current reality. Ofgem’s April to June 2026 average rates: 24.67p per kWh for electricity, 5.74p per kWh for gas. What changes the picture is efficiency. A heat pump with a COP of 3.0 produces 3 kWh of heat from every 1 kWh of electricity. At 24.67p input, that works out at about 8.2p per kWh of useful heat. A gas boiler at 90 percent efficiency delivers heat at roughly 6.4p per kWh. The gap is smaller than it looks. And it disappears entirely if you are comparing against oil, LPG or electric heating. Heating system Annual running cost vs heat pump Air source heat pump (COP 3.0) £800 to £1,100 Baseline Gas boiler, A-rated new £900 to £1,300 Similar or slightly more Oil boiler £1,400 to £2,000 40 to 80% more LPG boiler £1,600 to £2,200 60 to 100% more Electric storage heaters £2,200 to £3,000 More than double Estimates use Ofgem April to June 2026 price cap and average heating consumption for a 3-bed semi. Real costs vary with insulation quality, system design, and how the thermostat is used. The £7,500 grant: who gets it The Boiler Upgrade Scheme pays £7,500 directly to