Heat Pump Size Calculator
Get a ballpark design heat loss (for sizing) and annual heat demand (for running costs) for a home, then see which heat pumps in the database could cover it. Start with a quick estimate, or switch to the detailed version to refine it.
For residential properties only. This is an indicative planning tool, not a substitute for a full room-by-room heat loss survey — get one from an MCS-certified installer before sizing or buying a system.
Heat pumps that could cover this
Residential models from the database whose rated heating capacity covers the estimated design heat loss above: up to 6 air source (ASHP) and 2 ground source (GSHP) options.
Method: whole-dwelling fabric and ventilation heat loss following the CIBSE Domestic Heating Design Guide approach, using indicative UK regional design temperatures and degree-day data. U-values are typical defaults for the age band selected, not measured values for your actual property, and envelope areas are estimated from floor area, storeys and property shape rather than measured room-by-room. Figures exclude solar and internal gains, which in practice reduce real-world running costs somewhat. Always confirm sizing with a full MCS heat-loss survey before purchase — see our installation costs guide for what that typically involves.