Project Summary: How Ground Source heat pumps extract heat from the ground which can be used to provide your home with heating and hot water.
You can save up to £1,000 in energy bills per year with a ground source heat pump if you are currently using electric heating. Over and above these savings there are government grants of £1250 available for fitting a ground source heat pump, and in future they may qualify for the Renewable Heat Incentive which will make your returns even better. They are also eligible to be fully or part funded through the Green Deal scheme which pays for the installation costs. You then pay the scheme back using the savings made on your energy bills, which should make the installation free to you.
You will need enough space in your garden to bury a loop of piping called a 'ground loop' which extracts the heat from the ground, though the ground loop can be buried in vertical boreholes if space is limited.
There are other types of heat pump and they work on a very similar principle, instead extracting heat from different sources:
In England, Scotland and Wales ground source heat pumps do not normally require planning permission, however, you should check with your local authority to confirm that permission is not needed for your project. In order to qualify for the Renewable Heat Incentive subsidies the system must be fitted by a MCS accredited installer. Usual locations for the pump include your utility room, basement or even out in the garage.
Normally the loop is laid coiled in trenches about two metres deep, and a typical home would need around 600ft. A typical ground source installation for a 2 bed detached house would need (at least) two trenches about 12 inches wide and about 45m long. The trenches also need to be about 15 feet (5m) apart. The trenches will ideally be level to avoid making the pump work too hard and the wetter the ground the better as more heat is conducted. If you have limited space in your garden the loop can be buried vertically in the ground, usually to a depth of up to 10 metres for a typical home.
You will need to think about the following:
The efficiency of a heat pump is measured by it’s Coefficient of Performance (CoP); this is a measure of a heat pump’s ratio of heat output to electricity input, so the larger the figure, the more efficient the pump. Heat pumps can produce up to 4 kilowatts of heat energy for each kilowatt of electricity they use to generate this energy.
An alternative measure known as the System Efficiency Ratio (SER) has been devised by the Energy Saving Trust (EST). This is the ratio of how many units of electricity the whole heating system uses to run compared to the number of units of heat the pump produces. Both the SER and CoP range from around 1 to around 4. A recent study into heat pump performance has found that the mid-range SER for ground source heat pumps was around 2.3-2.5, with the most efficient units reaching 3.3.
The installation time for a ground source heat pump system does vary and depends on the size of the system. You can potentially save a significant amount of money on your installation bill by combining the installation with other building work and because of this the installation time will depend on this also.
Only MCS accredited installers are able to validate installations that qualify for the government’s Renewable Heat Incentive and Renewable Heat Premium Payment schemes. Installations carried out through the Green Deal must use Green Deal installers.
After the one-off installation cost of £6,000- £18,000, how much the system costs to run depends on a number of considerations - including how large and how well insulated your home is. Savings of more than £610 on your energy bills can be achieved annually if you are converting from an oil or electric heating system.
You could also receive a grant of £1,250 towards the system’s costs through the Renewable Heat Premium Payment scheme and regular payments for any heat generated through the Renewable Heat Incentive. To find out more about the Renewable Heat subsidies visit our Renewable Heat Incentive page.
You can also get your ground source heat pump installation either partially or fully funded through the Green Deal scheme. The Green Deal is effectively an affordable loan service for green home improvements. The scheme pays for the installation and you pay the scheme back monthly with the money you have saved on your energy bill. This means that the installation is “free” to you and should actually make saving overall, but it is not quite as good value for money as paying for the installation yourself as interest is included in your payments.
Heat pumps operate differently to oil and gas boilers in that they produce heat at lower temperatures over much longer periods. Because of this, during winter months it is best to leave them constantly switched on to heat your home efficiently. This might seem counter-intuitive at first but they do require a different mindset to operate efficiently.
You could make a saving of over £610 per year on your heating bills, although the amount does depend on your existing heating system. You can also get a one off payment of £1,250 through the Renewable Heat Premium Payment scheme and quarterly payments for the heat you generate if the pump is fitted by an MCS accredited installer. There are some additional benefits:
The savings you make by installing a heat pump will depend on several factors:
Here are some other related projects that you might find useful: