A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe – called a ground loop – which is buried in your garden. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump. This heat can then be used to heat radiators, underfloor or warm air heating systems and hot water in your home. The ground stays at a fairly constant temperature under the surface, so the heat pump can be used throughout the year – even in the middle of winter.
The length of the ground loop depends on the size of your home and the amount of heat you need. Longer loops can draw more heat from the ground, but need more space to be buried in. 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.
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.
How much you can save will depend on what system you use now, as well as what you are replacing it with. Your savings will be affected by:
Using the controls effectively will mean get the most out of your system. You may need to set the heating to come on for longer hours, but you may be able to set the thermostat lower and still feel comfortable.
Potential annual savings, in an average three-bedroom semi-detached home with a typical ground source heat pump installation:
| Existing System | Savings Per Year | Ground Source Heat Pump Performing at 250% | Ground Source Heat Pump Performing at 300% |
|---|---|---|---|
| Gas | £ Carbon Dioxide |
-£20 400kg |
£110 850kg |
| Electric | £ Carbon Dioxide |
£510 4,780kg |
£650 5,230kg |
| Oil | £ Carbon Dioxide |
£160 1,200kg |
£290 1,660kg |
| Solid | £ Carbon Dioxide |
£160 4,980kg |
£290 5,430kg |
A zero saving means it could cost you just as much to run the heat pump as the system you are replacing. We’ve assumed average boiler efficiency for each fuel type; ground source heat pumps produce more energy (as heat) than they use (as electricity), so their efficiency is more than 100%.
You may be able to receive payments for the heat you generate using a heat pump through the government’s Renewable Heat Incentive (RHI).
You may also be able to get help with the installation costs of a ground source heat pump through the Renewable Heat Premium Payment scheme.
Ground Source heat pump systems typically come with a ten year warranty. With regular maintenance, you can expect them to operate for 20 years or more. A yearly check by you and a more detailed check by us every three to five years should be sufficient.
In England, Scotland and Wales, domestic ground source heat pumps are generally allowed as permitted developments. We will advise you and provide assistance.
