Ground source heat pumps

A ground source heat pump, sometimes referred to 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 for your hot taps and showers.

Thermal transfer fluid (TTF), a mixture of water and antifreeze (sometimes known as ‘brine’) 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 with a diameter of around 180mm.

Heat from the ground is absorbed into the fluid, 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.

For further information on how a heat pump works, including details on typical savings, system design and control, see our in depth guide to heat pumps.

There are a few things to consider when deciding whether a ground source heat pump is right for you.

The cost of a ground source heat pump installation varies, influenced by:

• 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 newbuild or an existing property.
• Whether you’re opting to make any improvements to your radiators to improve the efficiency of the heat pump, or if you are installing radiators or underfloor heating for the first time.

Typical costs are around £28,000 if your ground loop is buried in trenches, and could be around £49,000 if you need to dig a borehole.

We recommend speaking to at least three installers to provide a quote for your heat pump system to give you the best idea of likely costs for your home.

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

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

You can see potential annual savings of installing a standard ground source heat pump, including any recommended radiator upgrades, in an average sized, four-bedroom detached home, below.

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.