Geothermal Heat pumps are energy efficient heating systems that utilize heat from the ground, rock, air or water where solar energy is stored.
The most common types of heat pumps used in the UK include:
- Outdoor Air Source, which harness heat energy from the outdoor air and deliver heat via a wet heating system like underfloor heating, radiators or fan convectors;
- Ground Source, where heat energy is collected from the ground or rock and delivers heat via a wet heating system;
- Water Source Heat, using heat energy pumped from an underground water source and deliversed via a wet heating system;
- Exhaust Air Damp, where stale air from the property's wet rooms is ducted to the heat pump and is the energy source for smaller, low energy dwellings;
- Air to Air Heat, which harnesses heat energy from the outdoor air and delivers heating and cooling via a fan convector.
Running costs for a property using a heat pump are reduced to the electricity required to run the heat pump, which means a saving of up to 60% compared to oil, LPG or all-electric heating. However usually they will not provide savings when compared to a gas boiler. Any form of heat pump will provide a lower temperature of background heat than one would expect from a traditional boiler, so they are usually fitted with underfloor heating or larger radiators running for longer periods of time at a lower temperature, rather than a blast of heat morning and evening as many people do with a traditional gas or oil fueled boiler system. Supplementary heating e.g. from a solid fuel stove, may be required in very cold periods. The Energy Saving Trust conducted an extensive field trial of heat pumps in 2012, finding that many heat pumps in the UK were poorly installed and performing much less efficiently than they should. Many systems are complex and controls are not always user-friendly, further contributing to poor performance.