Ground Source Heat Pumps
Horizontal Ground Loop
A horizontal ground loop is a network of sealed pipes buried in trenches. Water mixed with antifreeze circulates through the pipes. Because the fluid is cooler than the surrounding ground, heat passes into it and is carried back to the heat pump.
Drawing heat cools the ground around the pipes. Heat gradually flows back from the surrounding earth, so the loop must be sized for the building’s heat demand and the site’s ground conditions. This option needs enough suitable land for the trenches.
Costs & Grants
The cost of a ground source heat pump depends on the building, the heating system and how heat is collected. Horizontal loops require suitable land and excavation; boreholes require drilling. We assess the site and provide a quotation based on the work needed.
The Boiler Upgrade Scheme currently offers £7,500 towards an eligible ground source heat pump. Until 31 March 2027, this rises to £9,000 for eligible properties off the gas grid that are replacing oil or LPG heating. The grant is shown as a discount in the installer’s quotation.
Verticle Borehole
Where there is less space for trenches, sealed collector pipes can be installed in drilled boreholes. Fluid circulates down and back up the pipes, absorbing heat from the surrounding ground before returning to the heat pump.
Boreholes use much less surface area than a horizontal loop, but they require drilling. Their number and depth depend on the building’s heat demand and the ground conditions. In either design, the heat pump raises the collected heat to a useful temperature for heating and hot water.
What About the Garden?
Installing a horizontal loop means digging trenches, laying and testing the pipes, then backfilling the ground. The area may need time to settle before it is fully restored.
You can usually return the area above the loop to lawn or use it for shallow-rooted planting. Keep deep-rooted trees, permanent structures and future deep digging away from the buried pipes. Boreholes disturb less garden space, although the drilling rig still needs access. We’ll agree the pipe locations and what reinstatement is included before work begins.
