Air conditioning is a heat pump
Most modern split air conditioners are air-to-air heat pumps. In summer they move heat out of your room and outside. In winter they run in reverse: they take heat from the outside air (even cold air still holds heat) and move it into your room.
Does it actually feel warm?
Yes. The indoor unit blows warm air into the room, much like a fan heater, but uses far less electricity to do it. Many current models are designed to keep heating in outdoor temperatures well below freezing. Every unit lists its operating range, so it’s worth checking for the model you’re considering.
How efficient is it?
Heating efficiency is measured by SCOP, the seasonal coefficient of performance. A SCOP of 4 means that across a heating season, every 1 kWh of electricity delivers about 4 kWh of heat. A plug-in electric heater delivers 1 kWh of heat for every 1 kWh it uses.
Where it works best
- Heating the rooms you use, when you use them
- Rooms that are hard to heat: loft conversions, extensions, garden rooms
- Homes that want cooling in summer as well
Worth knowing
- It heats the air in the room. It doesn’t heat radiators or make hot water.
- The outdoor unit needs a place outside, usually on a wall or on the ground. Your installer will advise on placement and on any permissions you need.
- Indoor units are quiet. Outdoor units make some noise, so placement matters.