Heat Pump Sizing Calculator (Cornwall)
Estimate the right kW heat pump for your Cornwall home, including £7,500 BUS grant deduction and annual running costs at Q2 2026 tariffs.
How sizing works
A heat pump must match your property's heat-loss kW at design conditions (-2°C in Cornwall). We use indicative heat loss factors per property type and adjust by insulation level, then size the unit at 100-110% of peak demand. Real installations require a full MCS-compliant heat-loss calculation per room. Running costs assume SCOP 3.4 (ASHP) or 4.5 (GSHP), Octopus Cosy tariff blend (~14p/kWh average), and Cornwall typical heating-degree-days.