Heating systems: your home heating options explained

Ground source heat pumps

How does it work?
What are the benefits?
Is it right for me? 
How much does it cost?
What funding is available?
Will it save me money on my energy bills?
How do I get one?

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

In this guide we’ll take you through the benefits, how they work and how much they cost.

How does a ground source heat pump work?

It starts with a loop of pipe that’s 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.

Inside this pipe is a mixture of water and antifreeze called a thermal transfer fluid (TTF), sometimes known as ‘brine’.

The brine absorbs heat from the ground, which then passes through a heat exchanger into a refrigerant. The refrigerant is compressed, raising its temperature, and this heat is transferred again to your central heating system.

For a more detailed look at how a heat pump works, see our in-depth guide to heat pumps.

What are the benefits of a ground source heat pump?

The benefits of ground source heat pumps include:

Lower energy bills: switching to a heat pump could save you money compared to other ways of heating your home.
Reduce your energy use: for every unit of electricity they use, heat pumps generate three units of heat. Having a heating system this efficient means you cut down how much energy you’re using.
Improve your carbon footprint: heat pumps are a low carbon heating system, emitting less CO₂ emissions than other fuel sources.

Is a ground source heat pump right for me? 

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

You may also be deciding which is better: a ground source or air source heat pump?

You’ll need an area of land near your home where you can dig trenches or drill boreholes.

Digging trenches for a ground loop

If you have enough space, you can have a ground loop system. The ground needs to be suitable for digging and accessible to machinery from a road entrance. The area should have no 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. For a newbuild three-bedroom house, expect two trenches of 30-40 metres in length. If your home is larger or is an older property that isn’t as well insulated, you’ll need a bigger ground loop.

Boreholes

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. The ground is generally warmer the deeper you dig, so these systems can be more efficient than ground loop systems.

Larger houses may need more than one borehole. A borehole is only about 20cm wide, but somewhere between 75 and 200 metres deep. The depth of the borehole depends on the heat demand of your home and the underlying geology near your home.

Inside the house

You’ll need space inside your home for the indoor heat pump unit. The inside unit often contains the hot water cylinder and is roughly the size of an American-style fridge (about 120cm x 60cm x 60cm).
Blocks of flats can share large ground loops for their heat pumps. This is usually managed by installing the heat pump and pipework to the entire building at once, with maintenance costs built into other shared service charges.

Alternatively, you may wish to consider options such as air-to-air heat pumps. These systems are better suited for homes like small flats and park homes.

How much does a ground source heat pump cost to install?

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.

Generally, 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.
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 or if you’re installing radiators or underfloor heating for the first time.

What funding is available for ground source heat pumps?

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

For 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.

Will a ground source heat pump save me money on my energy bills?

Running costs depend on:

How your heat pump is designed.
How you control the heat pump.
Your electricity tariff.

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:

England, Scotland and Wales

Northern Ireland

How do I get a ground source heat pump?

Decide whether it's the right kind of heat pump for you

Use our free online assessment tool – GoRenewable – to help you find the right heating system for you.

Most heat pump installations are ‘permitted developments’ that don’t that don’t need planning permission.

But there are exceptions, for example if you live in a listed building or conservation area. It’s best to check with your local planning office, just in case.