Air source heat pumps (ASHP) absorb heat from the outside air in order to heat your home. Like other heat pumps, the heat generated by air source heat pumps can be used to power an underfloor heating system, heat radiators, or warm your home’s hot water cylinder. Like other heat pumps, air source heat pumps are highly energy efficient. For every 3 to 4 units of heat produced, approximately one unit of electricity is used.

A variety of air source heat pumps are available. Air to air heat pumps produce warm air, which can be pumped directly into a home or commercial building. Air to water heat pumps produce warm water, which can be used to power an underfloor heating system or warm radiators.

How do air source heat pumps work?

Air source heat pumps work using similar technology to that found in a modern fridge. Much like a fridge extracts heat using refrigerant, an air source heat pump extracts heat from the air outside your home and brings it inside to warm your living space, power an underfloor heating system or radiators, or heat the contents of your home’s hot water cylinder.

Air source heat pumps are made up of three elements: an evaporator coil, a compressor, and a heat exchanger. All of these parts play an important role in the process of warming your home or hot water system.

The evaporator coil is located inside the internal section of the heat pump. This component absorbs heat from outside air. The compressor pump then distributes refrigerant around the heat pump until it reaches the temperature required to transfer heat to the heat distribution system. The heat exchanger then transfers the heat generated by the compressor pump to warm air, which is pumped into the home, or warm water, which fills a home’s hot water cylinder.

Air to water heat pumps, which convert warm air into warm water, generally warm water to a lesser degree than a standard hot water boiler. As the water is generally heated to 35 to 45°C, it is ideal for use in an underfloor home heating system. Air to air systems spread warm air throughout the home using a fan.

How much does it cost to install an air source heat pump?

Most air source heat pumps cost between £6,000 and £9,000 to purchase and install. The ongoing running costs of an air source heat pump vary depending on the needs of the homeowner. In cooler climates, an air source heat pump can be more costly to operate than it would be in a warm climate. The application of the heat pump — for example, an underfloor heating system or interior fan — also affect the cost.