Ground Source Heat Pump
Ground source heat pumps (GSHPs) use pipes which are buried under the ground to extract heat from the ambient earth temperature. This heat can then be used to heat radiators, underfloor and hot water within your home.
A ground source heat pump circulates a mixture of water and antifreeze around a loop, (a ground loop) which is buried outside your property . Heat from the ground is then absorbed by the fluid and passes through an exchanger into a heat pump. The ground stays at a constant temperature under the surface, so it can be used throughout the seasons.
The length of the ground loop required depends on the size of your home and the amount of heat you will need. Longer loops will draw more heat from the ground, but need more space. If space is limited, a vertical borehole can be drilled instead.
The advantages of ground source heat pumps
- lower your fuel bills, especially if you replace conventional electric or gas heating
- it can provide you with income through the government’s Renewable Heat Incentive (RHI)
- it may lower home carbon emissions, depending on which fuel you are replacing
- no fuel deliveries required
- heat your home as well as your water
- minimal maintenance needed
Unlike gas lpg boilers, heat pumps deliver heat at lower temperatures over much longer periods of time.
Air source heat pumps are easier to install than ground source as they don't need any trenches or disruption, but they are less efficient than ground source heat pumps. Water source heat pumps can also be used to provide heating in homes near any water source.
How do ground source heat pumps work?
Heat from the ground is absorbed at low temperatures into a fluid inside a loop of pipe (a ground loop) buried underground. The fluid then passes through a compressor that raises it to a higher temperature, which can then heat water for the heating and hot water circuits of the house. The cooled ground-loop fluid passes back into the ground where it absorbs further energy from the ground in a continuous process as long as heating is required by the house.
Normally the loop is laid flat or coiled in trenches about two metres deep, but if there is not enough space in your garden you can install a vertical loop down into the ground to a depth of up to 100 metres for a typical domestic home. Although Heat pumps require a small amount of electricity to run, the heat they extract from the ground, the air, or water is constantly being renewed naturally.
Is a ground source heat pump suitable for me?
To tell if an air source heat pump is right for you, there are a few considerations:
- Is your garden suitable for a ground loop? It doesn't have to be very big, but the ground needs to be suitable for a borehole or a trench and accessible to the appropriate digging machinery.
- Is your home well insulated? Ground source heat pumps work best when producing heat at a lower temperature than traditional boilers, it's essential that your home is well insulated and draught-proofed for the heating system to be effective. We can help you here.
- What fuel will you be replacing? The system will pay for itself much more quickly if it's replacing an electricity, LPG or coal heating system.
- What type of heating system will you use? Ground source heat pumps can perform better with underfloor heating systems or warm air heating than with radiator-based systems because of the lower water temperatures required. Retro fitting with your existing radiators is common.
- Is the system intended for a new development? Yes! Combining the installation with other building work can reduce the cost and minimise disruption of installing the system.
You may also want to consider air source heat pumps, which extract heat from the outside air.