Is an air source heat pump better than a ground source heat pump?
Air source heat pumps (ASHP) are the most common type of heat pump in the UK. This is because they’re usually less expensive than ground source heat pumps (GSHP). They also involve much less disruption to install.
Also, not everyone has a large garden or land near their home. This is usually what you need to install a ground source heat pump.
If you have the space, you may be thinking whether to get a GSHP or an ASHP. Here’s a comparison to help you choose which heat pump is right for you.
Most heat pumps work in largely the same way. They take heat from the environment, raise the temperature, and transfer it to your central heating system.
The main difference between the two main types of heat pumps is where they get heat from:
For more information, see our in-depth guide to find out how heat pumps work.
A lot will depend on your circumstances. But some factors will make your decision between an air source and ground source heat pump simpler:
If you don’t have outdoor space available, you can rule out getting a ground source heat pump.
Installing a GSHP involves digging trenches or drilling boreholes for pipework. So, if you lack the outdoor space to do so, you’ll need to explore different options.
Most factors that influence the cost are common to both air source and ground source heat pumps, including:
For ground source heat pumps there’s extra work involved, including digging trenches or boreholes.
To compare, the typical cost of an air source heat pump is approximately £14,000.
Meanwhile, a ground source heat pump can cost around £28,000.
Thanks to the Boiler Upgrade scheme, there is funding available for both in England and Wales. You can get £7,500 off the cost of an air source or ground source heat pump. For more information, and for support if you live in Scotland or Northern Ireland, read our Boiler Upgrade Scheme blog.
The efficiency of a heat pump depends on the ‘source’ temperature. The colder the source temperature, the harder the heat pump needs work. This means your home’s location and the time of year can affect its efficiency.
Air source heat pumps take heat from the outside air. Air temperatures fluctuate between -5°C to 25°C for at least 95% of the year for most UK homes. But there have been extreme outliers. For example, the coldest ever air temperature recorded in the UK was -27°C in Braemar, Scotland.
Air source heat pumps can operate effectively in these extreme conditions, but this affects their efficiency .
Ground source heat pumps, however, extract heat from the soil. Here the temperature doesn’t reach as high, but it also doesn’t drop below freezing. Mostly, the soil temperature will stay above 5°C throughout the year.
This means there are many points during the year when an ASHP is more efficient than a GSHP. This is because the air temperature is warmer than the ground temperature.
However, when the weather is at its coldest, a GSHP can be more efficient than the ASHP. And this is when you’ll be using the heat pump most.
Unlike a ground source heat pump, an air source heat pump doesn’t need to use energy to pump fluid around the pipework outside. As a result, an ASHP can still be slightly more efficient on days there the air is the same temperature as the ground.
Overall, ground source heat pumps tend to be more efficient across the year. But there are plenty of other factors that affect a heat pump’s efficiency, regardless of the type.
You’ll get an efficient low carbon heating system whichever technology you go for, so long as you:
Both heat pump types may work in a similar way, but they have different setups and requirements.
Both could help you cut energy costs and heat your home efficiently, as well as improve your carbon footprint.
A ground source system is likely to be more efficient than an equivalent air source. This gives you lower running costs and lower CO2 emissions, but will cost more to install.
Unlike air source heat pumps, ground source heat pumps don’t need an outdoor unit. However, they do need a large indoor unit.
Generally speaking, if you’re limited by budget or space restrictions, an ASHP is more likely to suit you.
Your installer should discuss this with you in more detail to help you find the right solution.
We recommend getting quotes from at least three certified different installers who are with the Microgeneration Certification Scheme (MCS). You can find installers near you using the MCS website.
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Last updated: 3 February 2025