Heat Pump Grant Calculator (UK BUS 2026)

UK Heat Pump Guide 2026

The Boiler Upgrade Scheme (BUS) 2026

The BUS provides upfront grants for switching from fossil fuel heating to a heat pump or biomass boiler. Current grant levels (as of 2026/27): air source heat pump (ASHP) £7,500. Ground source heat pump (GSHP) £7,500. Biomass boiler £5,000 (rural off-gas-grid only). The grant is paid to the installer, who deducts it from your bill — you pay only the net cost. Eligibility: must be a MCS-certified installer; must be replacing fossil fuel heating; valid EPC required (no outstanding loft or cavity w

True Cost of Installation

Average UK heat pump installation costs 2026: ASHP £10,000-15,000 typical (£12,500 average) — net of grant: £2,500-7,500. GSHP £18,000-30,000 typical — net of grant: £10,500-22,500. Hybrid systems £8,000-14,000 typical. Additional costs that may apply: radiator upgrades (heat pumps work at lower flow temperatures, so existing radiators may be undersized) £100-300 per radiator replaced; hot water cylinder if you currently have a combi boiler £500-1,500; electrical supply upgrade £200-2,000 if exi

Running Cost Reality

The energy crisis years have changed heat pump economics significantly. As of 2026: heat pumps achieve real-world COP (coefficient of performance) of 2.5-3.5 in UK conditions. So 1 kWh of electricity produces 2.5-3.5 kWh of heat. Gas boilers have efficiency around 0.85-0.92 — 1 kWh of gas produces 0.85-0.92 kWh of heat. Current unit rates: electric ~28.6p/kWh, gas ~6.4p/kWh. Per useful kWh of heat: heat pump costs ~9-11p/kWh; gas boiler costs ~7-7.5p/kWh. THIS MEANS GAS IS STILL CHEAPER per kWh

When Heat Pumps Actually Pay Back Fast

Best-case scenarios: (1) Replacing oil heating in rural homes — oil at 7.5p/kWh × 0.85 efficiency = 8.8p/useful kWh; heat pump at 9-11p/useful kWh competitive PLUS no fuel deliveries. (2) Well-insulated newer homes where heat pump runs at high COP (3.5+) — drops cost to 8p/useful kWh, cheaper than gas. (3) Combined with solar PV that powers daytime heat pump operation — effectively free heat for sunny periods. (4) Octopus Cosy tariff — 4-6 hours/day of 13p/kWh electric — combined with thermal st