An air source heat pump takes heat from the air and boosts it to a higher temperature using a compressor. It then transfers the heat to the heating system in the home. It works a bit like a refrigerator in reverse.
1. The fan draws ambient air from the outside into the evaporator.
2. Liquid refrigerant absorbs the air's heat and evaporates into a vapour, even at low temperatures.
3. This vapour enters the compressor, where the pressure and temperature are increased.
4. The heated refrigerant passes through the condenser, transferring heat into home's heating and hot water system.
5. The refrigerant flow is then controlled by the expansion valve to continue heat pump operation.
In the summer, an air source heat pump won't draw as much electrical power as the ambient air has more heat to release. This is further helped by weather compensation automatically built into the heat pump controls.
The heat pump will still operate, giving heat when and if required, and provide heat to the hot water cylinder.
If a cold snap hits, the heat pump automatically adjusts its weather compensation making sure you are still comfortable.
Heat pumps will work even when the temperature drops to -25 degrees C. Even below freezing, there is still useable heat in the air that can be pulled through the heat pump and converted to heat in the building.
The heat pump will have to work harder to extract that heat, however most heat pumps are set up to work within a certain range, for example they are optimised to work between -10 and +20 degrees C.
Air source heat pumps are designed to work all the time, so with good design and good installation, they should not freeze in winter. If there's a power cut, the antifreeze in the system will stop the pipework from freezing.
Heat pumps will carry out an automatic 'defrost' operation, to break any ice forming on the fins as heat is extracted from the air. With our heat pumps, you shouldn't notice when the heat pump is defrosting.