Heat Pump Cost Calculator UK 2025/26

Air source heat pump (ASHP) installation costs in 2025/26 are typically £10,000–15,000 before the Boiler Upgrade Scheme (BUS) grant. The BUS grant is £7,500 for air source heat pumps, reducing your net cost to £2,500–7,500. Costs vary by property size, heat distribution system (underfloor heating or radiators), and whether pipework needs upgrading.

The BUS grant provides £7,500 towards the cost of an air source or ground source heat pump installed in eligible homes in England and Wales. The grant is paid directly to the installer, who deducts it from your quote. Properties must have a valid EPC and generally need loft and cavity wall insulation to be in place. The BUS runs until March 2028.

Ground source heat pump (GSHP) installation costs £20,000–35,000 depending on ground loop type (horizontal trenches vs vertical boreholes). Vertical boreholes cost more but require less land. The BUS grant of £7,500 applies to GSHPs too. Despite higher upfront costs, GSHPs have higher COP (efficiency) and typically lower running costs than ASHPs.

COP (Coefficient of Performance) measures efficiency: a COP of 3 means 3 units of heat output per unit of electricity input. ASHPs typically achieve COP 2.5–3.5 depending on outdoor temperature. GSHPs achieve COP 3.5–5.0. Higher COP = lower running costs. Annual running costs for a well-insulated 3-bedroom house are typically £700–1,200 for an ASHP vs £2,000+ for gas.

ASHPs are permitted development in England if: the unit is under 1m³, more than 1m from a property boundary, not on a wall or roof facing a highway, and noise conditions are met (42dB(A) at 1m from neighbour's window). Ground source heat pumps and horizontal collectors require permitted development consideration. Scotland, Wales, and Northern Ireland have different rules.

In 2025/26, electricity costs approximately 25p/kWh; gas approximately 6p/kWh. However, heat pumps operate at 250–350% efficiency (COP 2.5–3.5) vs gas boilers at ~90% efficiency. Net: heat pump at 25p ÷ 3 = ~8p/kWh of heat; gas boiler at 6p ÷ 0.9 = ~6.7p/kWh of heat. Running costs are broadly comparable currently, with heat pumps expected to become cheaper as electricity decarbonises.

Heat pumps work best with: good insulation (loft at 270mm, cavity walls, floor if possible), low-temperature heat distribution (underfloor heating or oversized radiators designed for 45°C flow temperature vs 70°C for gas). Many installers will assess your home and may require upgrading radiators in key rooms. MCS-certified installers provide a heat loss calculation.

MCS (Microgeneration Certification Scheme) certifies installers and products for small-scale renewable technology. You must use an MCS-certified installer to qualify for the Boiler Upgrade Scheme grant. MCS certification also ensures the installation meets quality standards and is eligible for any future government incentives. Check the MCS directory at gov.uk/find-an-energy-grant-for-your-home-heat-pump.

An ASHP installation typically takes 1–3 days for the external unit and internal pipework changes. If radiators need upgrading, add 1–2 days. Ground source horizontal collectors take 1–2 days for excavation; vertical boreholes 2–5 days depending on depth. An ASHP requires no large excavation and can often be installed with minimal disruption.

Heat pumps can work in older properties but are less efficient. A heat loss calculation by an MCS installer will determine whether your home needs insulation upgrades first. Many Victorian terraces have been successfully retrofitted with ASHPs after improving insulation. The key is ensuring the heat distribution system can deliver comfortable temperatures at lower flow temperatures.

The Smart Export Guarantee (SEG) applies to solar PV and micro-wind, not directly to heat pumps. However, if you have solar PV, the electricity it generates can power your heat pump, reducing running costs. Some heat pump tariffs (e.g. Octopus Cosy or Economy 7) offer off-peak electricity rates that significantly reduce ASHP running costs when timed correctly.

ASHP efficiency (COP) decreases as outdoor temperature falls. At -5°C, a typical ASHP runs at COP 1.5–2.0 vs 3.5 in mild weather. Modern cold climate ASHPs (rated to -25°C) maintain higher COPs in cold weather. In severe winter periods, an electrical backup element may activate, increasing running costs. Ground source heat pumps are more stable as ground temperatures remain relatively constant year-round.