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What is a ground source heat pump?

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.

Ground Source Heat Pump

Is a ground source heat pump right for me?

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

Is your properties grounds suitable?

You don’t necessarily need a large space, but you will need land near your home suitable for digging trenches or drilling boreholes.

Ground loop

The ground will need to be suitable for digging and accessible to machinery from a road entrance. The area will need to avoid trees, as roots will cause problems when digging trenches. The length of ground loop and trenches depend on the size of your home and the amount of heat you need.


If space is limited, it may be possible to drill vertical boreholes to gather heat. This is usually more expensive than digging trenches and usually needs a specialist ground (thermogeological) survey.

Larger houses may require more than one borehole. Borehole depth depends on the heat demand of a property and the underlying geology but is likely to be around 75-200 meters deep.

Inside the house

You will need space inside your home for the indoor heat pump unit, which contains key components. The inside unit often contains the hot water cylinder and is roughly the size of an American style fridge.


Will a heat pump save me money on my energy bill?

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.

Predicted Annual Savings

GSHP Annual Savings.jpg
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