What Size Heat Pump Do I Need?

The size of your heat pump, measured in kilowatts (kW), determines how much heat it can produce. Getting this right is one of the most important factors in a successful installation.

For a typical UK home, air source heat pumps range from 5 kW to 16 kW. A well-insulated two-bedroom flat might need just 5-6 kW. A three-bedroom semi-detached house typically needs 8-10 kW. A larger four or five-bedroom detached house might need 12-16 kW.

The sizing isn't based on floor area alone, it's calculated from a detailed room-by-room heat loss assessment. This considers wall insulation, glazing type, ceiling height, ventilation, floor construction, and the local climate.

An undersized heat pump will struggle to heat your home in cold weather, running constantly and driving up electricity costs. An oversized heat pump will cycle on and off too frequently, reducing efficiency and increasing wear on the compressor.

This is why the home survey is so crucial. Our MCS-certified engineers use industry-standard heat loss software to calculate exactly what your home needs, then select the appropriate heat pump model.

We design for the coldest expected conditions (typically -3°C to -5°C for most of England) so your system can handle anything a British winter throws at it.