Air and Ground Source heat pumps extract stored heat from the land or from the air surrounding a property, and pass this through a heat exchanger to warm up the water in a central heating system.
Ground source and air source heat pumps work most efficiently when raising water to a temperature of around 40C, and so are best matched to a wet under-floor heating system. As it is not normally possible to fit a wet under-floor heating system into an existing property, they are most commonly installed into new properties or when properties are being extended or refurbished.
Air Source Heat Pumps
Air source heat pumps are fitted onto the outside of a building, rather like an air-conditioning unit working in reverse. They can be retro-fitted onto many properties.
Air source heat pumps and ground source heat pumps are both eligible technologies for funding under the Domestic Renewable Heat Incentive and Non-Domestic Renewable Heat Incentive (RHI) Schemes.
Ground Source Heat Pumps
Ground source heat pumps work by extracting heat stored in the ground (which is replenished by the sun) and passing it through a heat exchanger to raise the temperature of water sufficiently to heat a home. They generally require external collector loops to be laid in the ground next to the property in trenches or boreholes.
As the heat source is the sun, the only energy used in a ground source heat pump system is in the pumps and compressors needed to run it.
