Air-source heat pump cost in the UK

An air-source heat pump installation is several distinct things in one quote. There is the outdoor unit itself; there is a heat-loss survey to size the system to the building; there is usually a new hot-water cylinder because the old direct cylinder will not match the lower flow temperature; there is some emitter work where individual radiators are undersized for a 45 °C flow; and there is the controls and commissioning that determines whether the system will actually run efficiently once you move in.

Most price variance lives in those parts of the quote that are not the unit. A quote that bundles them into a single number tells you less than a quote that breaks them out, even if both arrive at the same total. Ask for the heat-loss calculation and the emitter schedule as deliverables before you sign anything.

For a typical UK three-bedroom semi-detached or end-of-terrace house with no major fabric problems, an MCS-certified installer quoting a 7 kW R290 monoblock with a 200-litre cylinder will land in roughly the £10,500 to £14,500 range before the Boiler Upgrade Scheme grant. After the £7,500 grant, that sits at approximately £3,000 to £7,000 out of pocket.

Larger detached homes typically take a 10 to 14 kW unit and an upgraded cylinder, pushing the gross figure to around £13,000 to £18,000 before the grant. Solid-wall Victorian and Edwardian terraces add £2,000 to £4,000 to the installed figure because pipe routing, emitter upgrades and outdoor unit placement all become more involved.

Ground-source heat pumps are typically twice the installed cost of an air-source equivalent once the loop is included, although the same £7,500 BUS grant applies; they make sense in particular sites rather than as a general default.

First, emitter upgrades. A heat pump runs cooler than a boiler, so radiators sized for 70 °C may need to grow at 45 °C. A typical retrofit changes one to four radiators; the cost varies more with access than with the radiators themselves.

Second, cylinder upgrades. Most homes need a new indirect cylinder with a larger coil because a heat pump heats water more slowly than a gas boiler. A 200 to 250 litre cylinder is a common choice; relocating it adds disruption and cost.

Third, outdoor unit placement. A side-passage or front-garden install often costs less than a tight rear yard with limited clearance, because the pipework route and any acoustic enclosure are simpler.

Fourth, the building. A solid-wall Victorian terrace will need a bigger unit, more emitter work and longer pipe runs than a 1990s semi; that is the single largest archetype-level cost driver in the UK stock.

The Boiler Upgrade Scheme grant is administered by Ofgem on behalf of DESNZ. The MCS-certified installer applies for the grant on behalf of the customer, and the grant is paid to the installer; the homeowner sees it as a £7,500 deduction on the final invoice rather than a payment that arrives separately.

Eligibility centres on the property rather than the homeowner. The property must be in England or Wales, must have a valid EPC issued in the past ten years with no outstanding loft or cavity-wall recommendations, and must not have another government heating grant claimed on the same home. Owner-occupiers and small landlords are both eligible. The Northern Irish and Scottish equivalents work differently and are covered on the grants hub.

The figures here are drawn from the Energy Saving Trust's published heating cost guidance, from DESNZ's quarterly Boiler Upgrade Scheme statistics on average installed cost and grant value, and from MCS installer surveys. They are intentionally a range, not a single number. The published source for each value is linked in the evidence panel above; treat them as a sanity check for the quotes you receive rather than as a quote in themselves.