Grant rules checked against Ofgem on 15 October 2026
Air source vs ground source heat pump: which is right for you?
Published and last updated 15 October 2026
An air source heat pump takes heat from outside air and needs only a spot for the outdoor unit, while a ground source heat pump takes heat from pipes buried in trenches or boreholes and needs land and groundworks. Both get a £7,500 Boiler Upgrade Scheme grant, or £9,000 in eligible off-gas homes until 31 March 2027.
| Feature | Air source | Ground source |
|---|---|---|
| Heat source | Outside air | Pipes in trenches or boreholes |
| Outdoor space | Room for one unit | Land reachable by machinery, or space for boreholes |
| Typical installation | Varies by home; see our cost guide | Around £15,000 with trenches, more with boreholes (Energy Saving Trust) |
| Grant | £7,500 / £9,000 off-gas | £7,500 / £9,000 off-gas |
| Time to install after grant approval | 3 months | 6 months |
| Disruption | Low | Groundworks needed |
Which is cheaper to install?
Air source is almost always cheaper to install, because ground source needs trenches or boreholes; the Energy Saving Trust puts a trench-based ground source system at around £15,000.
How much space does ground source need?
Ground source needs land near the house that machinery can reach, or space for one or more boreholes.
The Energy Saving Trust example: a new three-bedroom house might need two trenches 30 to 40 metres long; boreholes are about 20cm wide and 75 to 200 metres deep.
Which is more efficient?
Ground source systems are generally more efficient in winter because ground temperature is steadier than air temperature, but a well-designed air source system can still heat a home efficiently.
Which suits North West homes?
Air source suits most North West homes, especially terraces and semis with small gardens, while ground source suits rural properties with land, such as farmhouses in Lancashire and Cumbria.
Frequently asked questions
Is the grant the same for both?
Yes.
Can a block of flats share a ground loop?
Yes, shared ground loops are eligible for the scheme.
Do both need a hot water cylinder?
Yes.