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Quick Answer
Ground source heat pumps are one of the most efficient heating systems available in the UK. They're also one of the most misunderstood. This guide covers how they work, what they cost, how they compare to air source heat pumps and whether they're worth the investment for your home.
What is a ground source heat pump?
A ground source heat pump extracts heat stored in the ground and uses it to warm your home and provide hot water. Unlike a gas boiler, which burns fuel to create heat, a ground source heat pump moves existing heat from one place to another. This makes it significantly more efficient than any combustion based heating system.
The heat is extracted through a network of pipes buried in your garden, either laid horizontally in trenches or vertically in boreholes drilled deep into the ground. A fluid circulates through those pipes, absorbs the heat from the ground and carries it into the heat pump unit inside your home. The heat pump then concentrates that energy and sends it through your radiators, underfloor heating or hot water cylinder.
How does a ground source heat pump work?
The process works in four stages.
• The ground loop fluid absorbs heat from the soil or rock underground.
• That fluid passes through a heat exchanger inside the pump, transferring its energy to a refrigerant.
• The refrigerant is compressed, which raises its temperature significantly.
• That heat is then transferred to your home's heating and hot water system.
The ground stays at a relatively constant temperature year round in the UK, typically between 8 and 12°C at shallow depths. This means a ground source heat pump works consistently whatever the weather.
Not sure whether a ground source or air source heat pump is right for your home? OVO's free survey will tell you. Book yours here.
Ground source vs air source heat pumps
Both systems work on the same principle but there are meaningful differences in cost, efficiency and what your property needs.
| Ground source | Air source | |
|---|---|---|
| Installed cost (before grant) | £18,000 to £35,000 | £8,000 to £15,000 |
| BUS grant | Up to £9,000 (£7,500 for gas, £9,000 for oil or LPG) | Up to £9,000 (£7,500 for gas, £9,000 for oil or LPG) |
| Outdoor space needed | Large garden or borehole | Small external wall space |
| Noise | Very quiet, no outdoor unit | Low hum from outdoor unit |
| Works in cold weather | Yes, very consistently | Yes, suitable for UK winters |
| Best for | Off-grid, large gardens, maximum efficiency | Most UK homes |
How much does a ground source heat pump cost in the UK?
Ground source heat pump costs vary significantly depending on whether you use a horizontal ground loop or a vertical borehole system.
| System type | Installed cost | After BUS grant |
|---|---|---|
| Horizontal ground loop, 3 to 4 bed home | £18,000 to £27,000 | £10,500 to £19,500 |
| Vertical borehole, 3 to 4 bed home | £22,000 to £35,000 | £14,500 to £27,500 |
| Horizontal ground loop, larger home | £25,000 to £35,000 | £17,500 to £27,500 |
These figures are before the Boiler Upgrade Scheme grant of up to £9,000 (£7,500 for gas, £9,000 for oil or LPG), which applies to ground source heat pumps as well as air source. After the grant, a horizontal system for a typical home could cost £10,500 to £19,500.
What affects the cost of a ground source heat pump?
Several factors influence the final price.
• System size. Larger homes with higher heat demand need a more powerful system and a larger ground loop, both of which increase cost.
• Ground loop type. Horizontal loops are cheaper to install but need more land. Vertical boreholes need specialist drilling equipment and are more expensive.
• Ground conditions. Rocky or difficult ground increases the cost of installing horizontal trenches or drilling boreholes.
• Existing heating system. If your home currently has radiators sized for a boiler, they may need replacing with larger radiators or underfloor heating to work efficiently with a heat pump's lower flow temperatures. This adds cost but your installer will advise during the survey.
• Hot water cylinder. Ground source heat pumps require a hot water cylinder. If you don't already have one, this adds to the installation cost.
Are ground source heat pumps worth it in the UK?
For the right property, yes. Ground source heat pumps deliver lower running costs than gas boilers and significantly lower carbon emissions.
The challenge is the higher upfront cost. The payback period for a ground source heat pump is typically longer than for an air source system, often 10 to 15 years depending on your current heating costs and energy tariff. After payback, the running cost savings continue for the life of the system, which is typically 20 to 25 years for the indoor unit.
| Your situation | Ground source suitable? |
|---|---|
| On oil or LPG heating | Yes, strong case |
| On mains gas | Air source likely better value |
| Large garden available | Yes |
| No outdoor space | Borehole only, higher cost |
| Well insulated home | Yes |
| Poorly insulated home | Improve insulation first |
| Planning to stay long term | Yes, payback period is longer |
| Shorter term ownership | Air source may suit better |
The Boiler Upgrade Scheme grant for ground source heat pumps
Ground source heat pumps are eligible for the Boiler Upgrade Scheme. The grant is £7,500 for most homes, or £9,000 for homes currently on heating oil or LPG. The grant applies to homes in England and Wales replacing an existing fossil fuel heating system.
The insulation requirement that previously applied was removed in April 2026, making more homes eligible. OVO checks your eligibility and handles the grant application as part of the free survey.
Can you combine a ground source heat pump with solar panels?
Yes, and it's a particularly effective combination. A ground source heat pump uses electricity to operate. Solar panels generate electricity. During daylight hours, surplus electricity from your solar panels can power the heat pump, reducing how much electricity you draw from the grid and lowering your running costs further.
OVO installs both ground source heat pumps and solar panels. If you're considering both, it's worth discussing a combined installation so the systems are designed to work together.
FAQs
How much does a ground source heat pump cost in the UK?
A typical ground source heat pump installation costs between £18,000 and £35,000 depending on whether you use a horizontal ground loop or vertical boreholes and the size of your home. After the Boiler Upgrade Scheme grant of up to £7,500, the net cost is typically £10,500 to £27,500.
What are the main differences between ground source and air source heat pumps?
The main differences are cost, installation requirements and outdoor space needed. Ground source systems cost more to install and need either a large garden for a horizontal loop or a borehole. Air source systems are cheaper and easier to install and suit most UK homes. Both are highly efficient heating systems that use significantly less energy than a gas boiler.
How much garden do you need for a ground source heat pump?
For a horizontal ground loop, you typically need 200 to 600m² of usable garden depending on system size. Vertical boreholes need far less surface space but cost more to drill. Your OVO surveyor will assess what's suitable for your property.
Can I get a grant for a ground source heat pump?
Yes. The Boiler Upgrade Scheme provides a grant of up to £7,500 for eligible homes in England and Wales. The insulation requirement was removed in April 2026, making more properties eligible. OVO checks your eligibility as part of the free survey at no cost.
Get your free heat pump survey from OVO. We'll assess whether a ground source or air source heat pump is right for your home and check your eligibility for the Boiler Upgrade Scheme grant.