Ground Source Heat Pumps

Ground Source Heat Pumps Explained

Ground Source Heat Pumps can heat your home and hot water by taking heat from the ground outside your home.  

The pump works by circulating Thermal transfer fluid (TTF) which is a mixture of water and antifreeze solution (sometimes called 'brine') through a pipe that is buried in your garden or outdoor space. This pipe 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.  

The heat from the ground enters the fluid in the pipe, which then passes through a heat exchanger and into the pump. This raises the temperature of the fluid, and then transfers that heat to the water in your home. This can help to heat your radiators or underfloor heating system, as well as your hot water cylinder for showers and taps. 

What to consider when thinking about a Ground source heat pump:

Are you considering installing a ground source heat pump in your home? There are a few important factors to take into consideration before making a decision.  

Firstly, you need to ensure that you have a suitable location for it. This doesn't necessarily mean you need a large space, but you will need land that is nearby and appropriate for digging trenches or drilling boreholes.  

If you decide to go with a ground loop option, you will need to make sure that the ground is easily accessible to machinery from the road entrance and free from trees whose roots could cause issues.  

The length of the ground loop and trenches will depend on the size of your home and the amount of heat you need. On the other hand, if you opt for boreholes, you will need to have enough space for vertical drilling, which is more expensive than digging trenches and usually requires a specialist ground survey.  

For larger houses, more than one borehole may be necessary, with the depth of each borehole dependent on the heat demand of your property and the underlying geology - typically around 75-200 metres deep. 

Lastly, you will need to allocate space for the indoor heat pump unit inside your home, which is roughly the size of an American-style fridge and often contains the hot water cylinder and other essential components. 

Useful links 

What is the most effective heat pump wet system? 

Air-to-air heat pumps as an alternative to a wet system 

What is the cost of a ground source heat pump? 

The cost of installing a ground source heat pump can vary depending on several factors. These include the type of ground loop you choose, whether you opt for trenches or a borehole, the brand, model, and size of the heat pump you select, the size of your property, and how much heat it requires. Additionally, the cost may differ based on whether your property is new or existing and whether you plan to improve your radiators for better heat pump efficiency or install radiators or underfloor heating for the first time. 

Typically, the cost of installing a ground source heat pump system is around £30,000 if you choose to lay the ground loop in trenches. However, it could be around £60,000 if you need to dig a borehole. We recommend that you speak to at least three installers to get quotes for your heat pump system to get the best idea of the likely costs for your home. 

If you reside in England or Wales, you may be eligible for £7,500 for a ground source heat pump under the Boiler Upgrade Scheme. 

What savings can I achieve with a ground source heat pump? 

To determine whether a ground source heat pump can save you money on your energy bills, you need to consider various factors, such as the design and operation of the heat pump system, as well as the type of system it is replacing. If you're considering installing a standard ground source heat pump in an average-sized, four-bedroom detached home, you may see considerable annual savings, especially if you also upgrade your radiators appropriately. For more detailed information on maximising your energy savings with a heat pump, please refer to our comprehensive guide.