Heat Pump Costs, the BUS Grant, and What Affects the Final Price
The installed cost of an air source heat pump (ASHP) typically runs from £7,000 to £15,000 before any grant. A ground source heat pump (GSHP) — which extracts heat from the ground via buried pipes — costs £15,000 to £35,000 due to the groundwork required and is more common in new builds or larger rural properties. The BUS grant of £7,500 applies to air source heat pumps and £7,500 to ground source heat pumps for eligible homeowners in England and Wales.
Several factors influence the total installation cost beyond the heat pump unit itself. If your existing radiators are sized for high-temperature water (75 to 80 degrees Celsius, typical of gas boiler systems), they may need replacing with larger radiators sized for the lower water temperatures that heat pumps operate at (35 to 55 degrees Celsius). Radiator upgrades can add £3,000 to £6,000 to the project. Alternatively, underfloor heating — which operates at very low flow temperatures and is ideal for heat pumps — can be installed as part of a renovation, but adds significantly more cost.
Homes that are poorly insulated will see reduced efficiency from a heat pump, as the lower operating temperatures require longer run times to maintain warmth. Most heat pump installers will recommend achieving at least EPC band C before installation, which may require loft insulation, cavity wall insulation, or more substantial external wall insulation. These measures can be included in the secured loan alongside the heat pump cost.
After the £7,500 BUS grant, a typical air source heat pump installation in a well-insulated three-bedroom house comes to £3,000 to £7,000 net. Including radiator upgrades or insulation works can push this to £8,000 to £15,000, at which point a secured loan provides the most cost-effective financing route.
Is My Home Suitable for a Heat Pump?
Heat pumps perform best in properties that are well insulated, draught-proofed, and ideally equipped with underfloor heating or oversized radiators. Before arranging a heat pump installation, a competent installer will carry out a heat loss calculation — a technical assessment of how much heat the property loses per hour at design conditions — to correctly size the unit and determine whether upgrades to the heat distribution system or the building fabric are required.
A property in EPC band C or above with cavity wall or solid wall insulation, loft insulation, and double or triple glazing is generally well suited to an air source heat pump. Properties in band D may work well with some upgrades. Band E or below typically require more substantial investment in the building fabric before a heat pump is cost-effective. An independent survey by an MCS-accredited heat pump installer will provide a detailed assessment of your specific property.
The legacy Renewable Heat Incentive (RHI), which paid households quarterly payments for heat generated by renewable systems, closed to new applications in 2022. Existing RHI recipients continue to receive payments for the duration of their seven-year agreement. If you installed a heat pump under the RHI, be aware that a secured loan on the property does not affect your RHI payments, as the scheme is based on the heat generated rather than ownership of the equipment.
Modern heat pumps operate quietly — typically 40 to 55 decibels at one metre, comparable to a refrigerator — and do not require planning permission under permitted development in most cases, subject to size and siting restrictions. Properties in conservation areas or listed buildings may require consent, and your installer will advise on this as part of the survey process.
