Air Source vs Ground Source Heat Pump: Which Is Right for You?

Both air source and ground source heat pumps extract low-grade heat from the environment and upgrade it to warm your home and hot water. The difference is where that heat comes from: air source pulls it from the outside air, ground source pulls it from pipes buried in your garden.

For the vast majority of UK homes, an air source heat pump is the right choice — but it is worth understanding why.

An air source heat pump for an average home is typically around £14,500 before grants. A ground source system is usually significantly more expensive because of the groundwork — either boreholes drilled deep into the ground or a large trenched "slinky" loop across the garden.

Both qualify for the £7,500 Boiler Upgrade Scheme grant (with the enhanced £9,000 available for eligible off-gas-grid homes on applications from 21 July 2026 to 31 March 2027), but the higher starting cost means ground source usually still costs more net.

Ground source has a theoretical efficiency edge because ground temperature is more stable than air across the year, which can lift the seasonal COP. However, a well-designed modern air source system already achieves a SCOP of 3.5 to 4.9 — more than enough to run cheaply.

In practice, a properly designed air source install closes most of the gap, at a fraction of the groundworks cost and disruption.

This is often the deciding factor. Ground source needs either room for deep boreholes or a large area of garden to trench a ground loop, plus the mess and cost of that groundwork. Many homes simply do not have the space.

An air source unit sits neatly outside against a wall and installs in days, not weeks, with minimal disruption. For most homes that practicality wins.

For the overwhelming majority of UK homes, air source is the sensible, cost-effective choice: lower upfront cost, quick low-disruption install, excellent efficiency when designed well, and the same grant support.

Ground source can make sense for larger rural properties with plenty of land, higher heat demands, or where the ground conditions are ideal — but it is a bigger commitment. We install air source heat pumps and will always tell you honestly if your situation points elsewhere.