Key takeaways
- Air source heat pumps are cheaper and simpler to install and suit most homes; ground source costs far more but runs more efficiently.
- Ground source needs space for ground loops or a borehole, which rules it out for many properties.
- The Boiler Upgrade Scheme gives £7,500 towards either type in England and Wales.
- For most households the question is really “air source or not”, with ground source reserved for larger homes with land.
Both air source and ground source heat pumps move heat rather than burn fuel, and both can run a whole home. The difference is where they draw heat from, what they cost to fit, and how efficiently they run. Here is how to choose.
Air source heat pumps
An air source heat pump takes heat from the outside air using a unit that sits outside the house, a bit like an air-conditioning box. It is the cheaper option to buy and install, fits most homes without major groundwork, and is by far the more common choice in the UK.
The catch: efficiency dips in very cold weather, exactly when you need the most heat, and the outdoor unit makes some noise and takes up wall or ground space. A well-sized unit in an insulated home handles this fine, but a poorly specified one struggles.
Ground source heat pumps
A ground source heat pump draws heat from the ground through buried pipes, either in long trenches or a deep borehole. Ground temperature is more stable than air, so it runs more efficiently year-round and tends to last a long time.
The catch: the installation is a major job and costs considerably more, because of the digging or drilling. You also need the land for trenches, or room and access for a borehole rig, which many homes simply do not have.
Which should you choose?
For most homes, an air source heat pump is the practical choice: lower cost, simpler install, and good performance in a well-insulated house. Ground source makes sense for larger properties with land, where the higher efficiency pays back over time. Either way, the Boiler Upgrade Scheme contributes £7,500 in England and Wales. See our guide to the best air source heat pumps and how a heat pump compares on cost in heat pump vs gas boiler.
FAQ
Is ground source more efficient than air source?
Generally yes, because ground temperature is steadier than air, especially in winter. That higher efficiency has to be weighed against a much larger installation cost and the need for land.
Do both types qualify for the £7,500 grant?
Yes. The Boiler Upgrade Scheme offers £7,500 towards an air source or a ground source heat pump in England and Wales, applied for by your MCS-certified installer. Off-gas-grid homes on oil or LPG can get more from 21 July 2026.
Which is right for an average home?
An air source heat pump suits most average homes thanks to its lower cost and simpler installation. Ground source is usually reserved for larger properties with the space and budget for the groundwork.