What a ground source heat pump is
A ground source heat pump takes heat from pipes buried in your garden instead of from the outside air. Water and antifreeze circulate through the pipes, pick up warmth from the soil, and the heat pump indoors concentrates it to heat your radiators and hot water. It costs noticeably more to install than an air source unit, mainly because of the digging or drilling, but it runs a little more efficiently and there is no fan unit on the outside wall.
It makes most sense for larger, rural homes with land, especially those off the gas grid. For a typical semi or terrace with a small garden, an air source heat pump usually does the same job for less.
Trenches or boreholes
The ground loop is the biggest decision and the biggest cost.
| Compare | Horizontal trenches | Vertical boreholes |
|---|---|---|
| How it works | Pipe laid in trenches about 1 to 2 metres deep | Pipe dropped down one or more deep drilled holes |
| Space needed | Large, open, reachable garden or paddock | Small footprint, room for a drilling rig |
| Disruption | Garden dug up, then reinstated | Less surface damage, but heavy kit on site |
| Cost | Lower of the two | Higher, because of specialist drilling |
| Best for | Rural plots with land to spare | Smaller plots, or where the ground suits drilling |
A good installer looks at soil type, access and space before recommending either. Ask why they chose one over the other.
What drives the price
There is no honest single price for ground source, because the ground works vary so much from site to site. Expect it to cost more than the £11,000 to £14,500 typical for an air source install (checked October 2026). The main factors:
- The ground loop. Trench length or borehole depth, set by how much heat the house needs.
- Access. Whether a digger or drilling rig can reach the spot easily.
- Heat pump size. Set by a room by room heat loss calculation, not by guesswork.
- Radiators and pipework. Some rooms may need larger radiators to work at lower water temperatures.
- Hot water cylinder. Usually needed, and usually part of the quote.
- Reinstatement. Putting the lawn or drive back after the work.
In England and Wales the Boiler Upgrade Scheme gives £7,500 off a ground source heat pump, the same figure as for air source. On a ground source job the grant covers a smaller share of the bill. Our installation cost guide sets out how the numbers usually add up.
How long it takes
The ground works usually come first and can take several days depending on the method and the weather. The indoor work, fitting the heat pump, cylinder and controls, follows and is similar to an air source install. Allow for the garden being out of use while the loop goes in.
Who it suits
- Detached homes with a large garden, field or paddock.
- Off-grid homes moving away from oil or LPG.
- Self-builds and major renovations, where the groundwork can be done alongside other work.
- Owners planning to stay long term, since the ground loop lasts for decades.
It suits less well if your garden is small with no rig access, you are moving within a few years, or the house loses heat fast and you have no plans to insulate.
Ask for the heat loss calculation, the ground loop design and the expected seasonal efficiency (SCOP) in writing. If a quote gives a price without these, you cannot judge it.
Choosing an installer
Ground source is specialist work. The installer must be MCS certified for ground source to claim the grant, and many subcontract the drilling, so ask who does it and who is responsible if the loop underperforms. You can check certification on the MCS register. City Boiler connects you with independent MCS-certified installers and checks certification before they quote.
If you are unsure whether ground or air source suits your home better, start with our heat pump installation overview.
Common questions
Is a ground source heat pump more efficient than air source?
Usually, yes. The ground a metre or two down stays at a fairly steady temperature all year, so the heat pump does less work in a cold snap than one pulling heat from freezing air. The gap in running costs is real but modest, and it rarely covers the extra installation cost quickly on its own.
Can I get the Boiler Upgrade Scheme grant for ground source?
Yes. In England and Wales the scheme gives £7,500 off a ground source heat pump, the same as air source, as of October 2026. Your MCS-certified installer applies for it and takes it off your bill. Check the current rules before you commit.
Do I need a big garden?
For horizontal trenches, yes, you need a sizeable open area that diggers can reach. If space is tight, vertical boreholes can work in a much smaller footprint, but drilling costs more.
Does ground source need planning permission?
Ground source installs at a single house are usually permitted development in England, but conditions apply and listed buildings and conservation areas are different. Your installer should check this before quoting. Check the current rules for your nation.