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Generating renewable energy

Ground source heat pumps

Benefits

  • could lower your fuel bills
  • reduce your household carbon footprint
  • heat your home as well as your water

Ground source heat pumps (GSHPs) use pipes that are buried in the garden to extract heat from the ground. This heat can then be used to heat radiators, underfloor or warm air heating systems and hot water in your home.

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.

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. If space is limited, a vertical borehole can be drilled instead.

How does a ground source heat pump 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.

If there is enough space, the collector loop can be laid horizontally in a trench about a metre or so below ground. Where there isn’t room to do this, you can drill vertical boreholes to extract heat from much further down, typically between 90m and 160m deep.

The space you need for a horizontal loop, and the depth you need for a borehole, will depend on many factors. Your heat pump installer will design the collector array based on local conditions and the heat requirements of your home.

Heat pumps have some impact on the environment as they need electricity to run, but the heat they extract from the ground, the air, or water is constantly being renewed naturally.

Watch our explainer video below:

Benefits of ground source heat pumps

It could lower your fuel bills, especially if you replace conventional electric heating.

It could provide you with an income through the government’s Renewable Heat Incentive (RHI).

It could lower home carbon emissions, depending on which fuel you are replacing.

There are no fuel deliveries needed.

It will heat your home as well as your water.

There is minimal maintenance required.

Unlike gas and oil boilers, heat pumps deliver heat at lower temperatures over much longer periods.

In winter, it may need to be on constantly to heat your home efficiently, but radiators won’t feel as hot to the touch as with a gas or oil boiler.

Often they are more difficult to install than air source heat pumps, but ground source heat pumps are often more energy efficient.

Is a ground source heat pump right for your home?

Here are a few key questions to consider to find out if a ground source heat pump is suitable for your home and needs:

Costs, savings and financial support

Costs

Installing a typical system costs around £14,000 to £19,000. Running costs will depend on a number of factors including the size of your home and how well insulated it is.

Savings

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:

Your heat distribution system

Underfloor heating can be more efficient than radiators because the water doesn’t need to be so hot. If underfloor heating isn’t possible, use the largest radiators you can. Your installer should be able to advise on this.

Your fuel costs

You will still have to pay fuel bills with a heat pump because they are powered by electricity, but you will save on the fuel you are replacing. If the fuel you are replacing is expensive you are more likely to make a saving.

Your old heating system

If your old heating system was inefficient, you are more likely to see lower running costs with a new heat pump.

Water heating

If the heat pump is providing hot water, then this could limit the overall efficiency. You might want to consider solar water heating to provide hot water in the summer and help maintain your heat pump efficiency.

Using controls

Learn how to control the system so you can get the most out of it. You will probably need to set the heating to come on for longer hours, but you might be able to set the thermostat lower and still feel comfortable. Your installer should explain to you how to control the system so you can use it most effectively.

England, Scotland and Wales

Northern Ireland

The saving you can expect will depend on the size of your home, any heating system upgrade and fuel type being replaced. You can expect the saving to range between old and new, depending on the age of your current heating system.

See the Renewable Heat Incentive page for the latest information and proposed changes to the RHI scheme.

Financial support

You may be able to receive payments for the heat you generate using a heat pump through the UK Government’s Renewable Heat Incentive.

Domestic RHI is no longer available in Northern Ireland. Details of the previous scheme can be viewed at NI Direct.

Installation

If you’re planning to install a ground source heat pump in your home, you need to register the energy device with your Distribution Network Operator (DNO). The DNO is the company responsible for bringing electricity to your home. Usually, your installer will register the device for you.

The UK Government has advice on how to register your new energy device in England, Scotland and Wales.

Maintenance

Heat pump systems typically come with a warranty of two to three years. Workmanship warranties for heat pumps can last up to 10 years, for example through Quality Assured National Warranties (QANW).

Many manufacturers also offer optional extensions of warranty for a fee.

You can expect them to operate for 20 years or more, but they do require regular scheduled maintenance.

A yearly check by you and a more detailed check by a professional installer every three to five years should be sufficient.

The installer should leave written details of any maintenance checks you should undertake to ensure everything is working properly. Consult with your supplier for exact maintenance requirements before you commit to installing a heat pump.

The Ground Source Heat Pump Association says there is no need for safety checks for ground source heat pumps and routine maintenance requirements are very low.

These may include pre-heating season checks of the water pump, external pipes and fittings and electronics.

Planning permission

Domestic ground source heat pumps are generally allowed as permitted developments, but check with your local authority to find out whether you need planning permission or not.

Last updated: 20 July 2021