Heat pump

A heat pump works like a fridge, but the warm side faces the house. A fluid called a refrigerant picks up heat outside, even from cold air, a compressor raises its temperature, and the heat goes into radiators, underfloor pipes or the indoor air. Because the electricity moves heat instead of making it, a heat pump delivers more heat than the electricity it uses; how much more is its coefficient of performance. Air-to-water models feed radiators and hot water; air-to-air models blow warm air and often cool too.

Efficiency falls when the outside air is very cold or the radiator water must be very hot, so insulation and correct sizing by a qualified installer matter. Part of a home’s HVAC, a connected heat pump can run more in cheaper hours on a time-of-use tariff. See IoT in energy.

If you already have radiators, Can a heat pump work with my existing radiators? explains the water temperature they need and a test you can do in winter with your current boiler.

In a flat, an air conditioner that also heats is an air-to-air heat pump: Can I heat a flat with a heat pump or an air conditioner? covers running costs, the energy label and the rules for outdoor units.

Part of the IoT Glossary. Spotted an error or a missing term? Tell us.