Heat Pump Costs by Property Size in 2026
A 1-2 bedroom home needs a 5-6kW heat pump costing £7,000-£10,000 before the grant. After the £7,500 BUS grant, that drops to £0-£2,500 — many smaller homes are fully covered. A 3-bed semi needs 8-10kW at £8,000-£13,000 (£500-£5,500 after grant). A 4-bed detached needs 10-12kW at £11,000-£18,000 (£3,500-£10,500 after grant). The BUS grant budget was doubled to £295 million for 2025/26 and extended through at least 2028, with over 100,000 applications processed by mid-2025.
Running Costs vs Gas and Oil
Modern heat pumps achieve seasonal COP (SCOP) of 2.8-4.5. At SCOP 3.6, every £1 of electricity produces £3.60 of heat. Octopus Energy's Cosy heat pump fleet averaged a real-world COP of 3.87 across 90 days. On standard tariffs, a heat pump at SCOP 3.6 costs roughly £610-£720/year for a typical home — comparable to gas at £650-£750. On smart tariffs like Cosy Octopus (11.7p/kWh off-peak), heat pumps deliver savings of £250-£400/year over gas. Against oil boilers, savings reach 30-50%; against electric storage heaters, 60-70%.
Best Heat Pump Brands for 2026
Daikin Altherma 3 H HT leads on efficiency with SCOP up to 5.43, A+++ rated, reaching 70°C flow temperature at just 38 dB. Vaillant aroTHERM Plus offers Quiet Mark certification and R290 natural refrigerant with 75°C flow. Mitsubishi Ecodan R290 is the UK market leader with the largest installer network. Samsung EHS Mono provides excellent value in a compact unit. Grant Aerona³ R32 is the budget-friendly installer favourite with SCOP up to 5.0+. We install all five brands and recommend based on your property during the free survey.
Pairing Heat Pumps with Underfloor Heating
Underfloor heating is the gold standard pairing for heat pumps. UFH operates at 30-40°C flow temperature, perfectly matched to heat pump efficiency. Heat pumps achieve COP 3.5-4.0 with UFH versus just 2.0-2.5 with older radiators. Every 5°C reduction in flow temperature improves COP by 0.3-0.4, cutting running costs 10-15% per 5°C step. UFH with heat pumps delivers 40-50% lower running costs than radiators with heat pumps. Wet UFH costs £70-£100/m² in new-build or £95-£190/m² retrofit.
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