Ground source heat pumps

A ground source heat pump (also known as a ground-to-water heat pump) transfers heat from the ground outside your home to heat your radiators or underfloor heating. It can also heat water stored in a hot water cylinder, ready to use for your hot taps and showers.

How does a ground source heat pump work?

Thermal transfer fluid (TTF), sometimes known as ‘brine’, is a mixture of water and antifreeze that flows around a loop of pipe buried in your garden or outdoor space. This loop could either be a long or coiled pipe buried in trenches, or a long loop (called a ‘probe’) inserted into a borehole.

Heat from the ground is absorbed into the brine, which then passes through a heat exchanger into the heat pump. This raises the temperature of the fluid and then transfers that heat to water.

See our in-depth guide to heat pumps for more information on how a heat pump works.

There are a few things to consider when thinking about installing a ground source heat pump.

You can use our online assessment tool, Go Renewable, to find out what renewable technologies, like heat pumps, are suitable for your home.

Here are a few questions you should ask yourself:

The benefits of ground source heat pumps include:

• Lower your energy bills: switching to a heat pump could save you money compared to other ways of heating your home. Find out more.
• Reduce your energy usage: because the heat energy delivered to your home by a heat pump is more than the electricity it uses, you can cut down on your energy usage.
• Cut your carbon emissions: as they’re a low carbon heating source, heat pumps emit less carbon than gas or oil boilers.

There are some other things that you need to consider when it comes to ground source heat pumps. You should think about:

• Installation costs: ground source heat pumps can typically cost £28,000 if your ground loop is buried in trenches, or £57,000 if you need to dig a borehole. Depending on where you live, you may be able to get funding.
• Having outdoor space: you might not have the space required to dig the trenches or drill boreholes required for a ground source heat pump. Explore different options for heating your home.

The cost of a ground source heat pump installation varies depending on several factors:

• Access to the ground and whether you choose trenches or a borehole to lay the ground loop.
• The brand, model and size of heat pump chosen.
• The size of the property and how much heat it needs.
• Whether it’s a new build or an existing property.
• Whether you choose to upgrade your radiators to improve the efficiency of the heat pump, or if you are installing radiators or underfloor heating for the first time.

Installing a ground source heat pump is typically around £28,000 if your ground loop is buried in trenches (if you need to dig a borehole, this cost will be considerably more).

Running costs will depend on how your heat pump is designed and how it’s operated. Savings on your energy bill will also depend on the system you’re replacing.

If you live somewhere that regularly experiences very cold air temperatures, a ground source heat pump might be more efficient than an air source heat pump.

This is because the ground temperature tends to be warmer than the air temperature throughout the year. Whether it’s more efficient enough to justify the extra cost will depend on the temperature of the ground where you live compared to the air temperature.

For more information, head to our in-depth guide to find out how to get the most out of your heat pump and maximise your savings.

Here are the potential annual savings of installing a standard ground source heat pump, including any recommended radiator upgrades, in a four-bedroom detached home:

If you live in England and Wales, you can get £7,500 towards a ground source heat pump with the Boiler Upgrade Scheme.

If you live in Scotland, you might be able to get an interest-free loan or a grant to make your home more energy efficient.

If you live in Northern Ireland, there isn’t a specific grant currently available but you can still ‘get heat pump ready’ and apply for funding for insulation via NI Energy Advice.