What is a heat pump?

A heat pump produces heat using energy absorbed from the outside air.

Air source heat pumps absorb heat from the outside air. This heat can then be used to heat radiators, underfloor heating systems, or warm air convectors and hot water.

An air source heat pump extracts heat from the outside air in the same way that a fridge extracts heat from its inside. It can get heat from the air even when the  temperature is as low as -15° C. Heat pumps have some impact on the environment as they need electricity to run, but the heat they extract from the ground, air, or water is constantly being renewed naturally.

Air source heat pumps (also known as ASHPs):

• could lower your fuel bills, especially if you are replacing conventional electric heating
• could provide you with an income through the government’s Renewable Heat Incentive (RHI)
• could lower your home’s carbon emissions, depending on which fuel you are replacing
• don't need fuel deliveries
• can heat your home and provide and hot water
• need little maintenance - they're called ‘fit and forget’ technology
• can be easier to install than a ground source heat pump, though efficiencies may be lower.

Unlike gas and oil boilers, heat pumps deliver heat at lower temperatures over much longer periods. During the winter they may need to be on constantly to heat your home efficiently. You will also notice that radiators won't feel as hot to the touch as they might do when you are using a gas or oil boiler.

How do air source heat pumps work?

Heat from the air is absorbed at low temperature into a fluid. This fluid then passes through a compressor where its temperature is increased, and transfers its higher temperature heat to the heating and hot water circuits of the house. There are two main types of air source heat pump system:

• An air-to-water system distributes heat via your wet central heating system. Heat pumps work much more efficiently at a lower temperature than a standard boiler system would. So they are more suitable for underfloor heating systems or larger radiators, which give out heat at lower temperatures over longer periods of time.
• An air-to-air system produces warm air which is circulated by fans to heat your home. They are unlikely to provide you with hot water as well.