Ground source heat pumps explained in plain terms, ground source heat pumps are one of the most efficient and environmentally friendly ways to heat a home. They work by extracting ground source heat from below the surface and using it to deliver space heating and hot water through an energy-efficient heating system. The UK government is incentivising a switch away from gas boilers and burning fossil fuels toward renewable heating, so a ground source heat pump grant may be available through the Boiler Upgrade Scheme to help reduce installation costs.
But what are ground source heat pumps? How does a heat pump work? And what ground source heat pump benefits can be expected after heat pump installations? These are the questions covered in this guide: ground source heat pumps explained.
Interested in installing a ground source heat pump in a home? Enter a postcode here to find out what financial assistance may be available.
What are ground source heat pumps?
Ground source heat pumps explained: GSHPs are source heat pumps that extract heat from the ground and use it to warm a home. They are often seen as a stronger long-term alternative to traditional heating systems because they offer high heat pump efficiency and can help reduce carbon emissions (they produce no carbon emissions at the point of use).
GSHPs use ground loops (a ground loop system) to draw free heat from underground, where the ground temperature stays stable at roughly 10–12°C year-round, even when air temperature drops in cold weather. That stable, consistent temperature helps GSHPs keep higher efficiency through the seasons, with less performance variation than air source heat pumps.
There are three main elements to a ground source heat pump: the heat pump itself, a ground heat exchange loop, and a heat distribution system.
- The heat pump extracts heat from the ground and converts it into usable heat energy.
- The ground heat exchange loop (ground loops) is a network of pipes containing thermal transfer fluid that absorbs heat and enables heat transfer back to the unit.
- The heat distribution system delivers warmth into a wet central heating system via radiators or underfloor heating systems (including underfloor heating).
Within these elements, the key components are the heat exchanger, the compressor, and the condenser. The heat exchanger inside the unit helps transfer heat from the ground loop into the refrigerant cycle. The refrigerant absorbs the energy absorbed from the ground, boils at a low temperature into a gas, and then the compressor raises its temperature further. This upgraded heat can meet the required temperature for heating, and in some setups can reach higher output temperatures (often more than 60°C if needed), depending on design and higher flow temperature requirements.
How efficient are ground source heat pumps?
Ground source heat pumps explained with performance in mind: GSHPs typically achieve 300–400% energy efficiency, meaning for every unit of electrical energy (or electricity consumed) used, they can deliver three to four units of usable heat. In technical terms, the coefficient of performance (COP) is often around 3 to 4, while a seasonal coefficient of performance (SCOP) gives a more realistic year-round average.
Because the ground stays stable, GSHPs are usually more efficient than air source heat pumps during cold weather, when outdoor air is less able to provide heat. That efficiency can translate into energy savings, lower energy bills, and fewer shocks from changing energy prices. The Energy Saving Trust has estimated that replacing an old (G rated) boiler may save up to around £550 per year on heating bills, depending on the home and existing system.
Interested in installing a ground source heat pump in a home? Enter a postcode here to find out what financial assistance may be available.
How to maximise your GSHP efficiency
To keep heat pump efficiency high and reduce running costs, consider these practical steps:
Use renewable energy options
If available, use renewable energy (such as solar PV) to power the heat pump. Pairing the system with renewables can reduce carbon footprint and improve overall household energy balance.
Support peak demand smartly
If extra heat is needed during very low temperatures or higher heat demand, targeted electric heating (like efficient room heaters) can be used carefully instead of turning up the entire central heating system. This can help manage consumption, especially when electricity is from renewables, and can work efficiently alongside an electric heating system.
How are ground source heat pumps installed?
Ground source heat pumps are installed by a qualified engineer. The process usually includes fitting the ground loop (outside) and the indoor unit (inside), then connecting into the home’s heating and hot water setup. GSHPs can provide heating and hot water all year round.
Outside installation depends on the loop type:
- Horizontal systems use trenches with pipes laid in the ground (a common approach for homes with more land).
- Vertical systems use drilled boreholes (often 40–120 metres deep), suitable where outdoor space is limited.
In most cases, installation is considered permitted development and does not usually require planning permission, though exceptions can apply (for example, protected areas or specific property conditions). Because excavation can be disruptive, it may be worth letting neighbours know in advance.
How much space do you need for a ground source heat pump?
Ground source heat pumps explained honestly: space is one of the biggest considerations. For horizontal ground loops, a significant land area is usually required, often in the region of roughly 600m² to 1200m² depending on the property, soil conditions, and how much heat the home needs (some systems may be quoted around 700–800 square metres as a general benchmark for typical installs). The ground loops are commonly buried at around 1 metre depth, while boreholes go much deeper.
For properties with limited outdoor space, vertical boreholes can reduce the footprint but typically involve deeper drilling and higher costs.
Indoors, there must also be space for the indoor heat pump unit and often a hot water cylinder, since GSHPs can heat water stored in the cylinder ready for taps and showers.
How much do ground source heat pumps cost?
Costs vary by system size, loop type, and site conditions. Here are common examples:
- 6–8KW Horizontal ground source heat pump: £10,000 – £12,500
- 12KW Horizontal ground source heat pump: £15,500 – £17,500
- 12KW Vertical system (requires extensive excavation/drilling): Up to £30,000
Maintenance is usually low compared with many other heating systems and can often be around £100 per year. GSHPs also tend to have long lifespans: ground loops can last 50+ years, while the indoor unit often lasts 20–25 years.
Government grants available for ground source heat pumps
Installing a GSHP can involve high installation costs, so government support may help offset the upfront spend.
Ground source heat pump grant (Boiler Upgrade Scheme)
This grant can be worth up to £7,500 for eligible installations and can help reduce the initial cost. Enter a postcode here to check eligibility.
ECO Scheme
The Energy Company Obligation (ECO) scheme can help fund energy-saving improvements, including heating upgrades and insulation measures that improve overall energy efficiency and can further reduce energy bills.
How to apply for financial assistance
To apply for funding, contact the relevant scheme provider or a local energy supplier/installer who can confirm eligibility and guide the application steps.
Interested in installing a ground source heat pump in a home? Enter a postcode here to find out what financial assistance may be available.
Benefits of ground source heat pumps
Here are the main ground source heat pump benefits to consider:
Cheaper energy bills
Because they are highly efficient, GSHPs can reduce heating costs, often estimated around 30–50% compared to fossil fuels, depending on the home, insulation, and system design.
Low carbon heating
GSHPs are a low-carbon option and produce no point-of-use emissions or local air pollution. They can significantly cut reliance on combustion systems and help reduce overall emissions.
Consistent performance all year
Stable ground temperatures allow reliable heat output regardless of outdoor weather, and GSHPs often outperform air source heat pumps in colder conditions.
Low maintenance
GSHPs generally have low maintenance requirements and do not always require annual servicing in the same way some combustion systems do (though checks are still recommended for performance and safety).
Drawbacks of installing a ground source heat pump
Expensive installation
One of the main disadvantages of a ground source heat pump is the upfront cost. Installation is typically more expensive than air source heat pumps and many other heating systems due to excavation work, ground loops, and specialist labour.
Depending on the size of the property and whether horizontal loops or vertical boreholes are required, costs can be high. While government grants such as the Boiler Upgrade Scheme can help reduce the financial burden, homeowners still need to plan for a higher initial investment compared to traditional gas boilers.
Intrusive excavation
Installing a ground source system usually involves digging trenches for horizontal loops or drilling boreholes for vertical systems. Horizontal loop installations, in particular, can be disruptive because they require substantial outdoor excavation.
Lawns, driveways, and landscaped gardens may need to be disturbed during the process. Although the area is restored once installation is complete, the temporary disruption can be inconvenient for homeowners.
Space requirements
Ground source heat pumps require adequate outdoor space. Horizontal ground loops need a large surface area, which may not be practical for smaller properties.
In such cases, vertical boreholes are a more realistic solution, but they involve deeper drilling and can increase installation costs. Additionally, indoor space is needed for the heat pump unit and often a hot water cylinder.
Alternatives to ground source heat pumps
Gas Boiler
A gas boiler remains the most common heating option in the UK. It is typically cheaper to install and easier to maintain. However, it is less energy efficient and produces higher carbon emissions compared to a GSHP. Some homeowners may opt for a hybrid system combining a heat pump with a boiler to meet higher heat demand.
Air Source Heat Pump
Air source heat pumps are also low-carbon and energy efficient. They are generally cheaper to install than ground source systems and may qualify for similar grants. However, their efficiency can vary depending on outdoor temperatures, especially during colder months.
Conclusion
This guide, ground source heat pumps explained, has explored how GSHPs operate, including how they extract heat from stable underground temperatures and convert it into usable energy for space heating and hot water. By relying on consistent ground temperatures rather than fluctuating air conditions, these systems can maintain strong performance throughout the year. The guide has also covered installation requirements, including the need for ground loops or boreholes, indoor space for the heat pump unit, and potential excavation work.
In addition, it has outlined typical costs, available government grants, and the long-term savings that can help offset higher upfront investment. Comparisons with gas boilers and air source heat pumps provide useful context for homeowners weighing different renewable heating options.
For those considering a switch from fossil fuels, the ground source heat pumps explained here should provide clarity and confidence. By understanding efficiency levels, space requirements, and funding support, homeowners can make a well-informed decision that aligns with their property size, heating demand, environmental goals, and overall budget.
FAQs – Ground Source Heat Pumps Explained
Are ground source heat pumps more environmentally friendly than gas boilers?
Yes. Ground source heat pumps produce no carbon emissions at the point of use and do not create air pollution. Unlike gas boilers that burn fossil fuels, GSHPs use renewable heat stored underground. This helps reduce carbon emissions, combat air pollution, and significantly lower a home’s overall carbon footprint.
Are ground source heat pumps more efficient than air source heat pumps in cold weather?
Generally, yes. Ground temperatures remain stable year-round, so GSHPs maintain higher efficiency in colder conditions. A typical ground source heat pump operates at 320–420% efficiency (COP 3–4), compared to 280–380% for air source systems, making performance more consistent during winter months.
How are ground source heat pumps installed, and do they need planning permission?
GSHPs can be installed using horizontal ground loops buried around 1 metre deep or vertical boreholes drilled 40–120 metres down. Boreholes suit properties with limited space. Installation is usually considered permitted development and does not normally require planning permission, with some specific exceptions.
Do ground source heat pumps require much maintenance?
Ground source heat pumps have relatively low maintenance requirements and typically do not require annual servicing like gas boilers. The underground loops can last over 50 years, and the indoor unit around 20–25 years. This makes them a durable and low-maintenance heating solution long term.
How much can you save with a ground source heat pump?
GSHPs can reduce heating bills by 30–50% compared to fossil fuel systems. Homeowners may save up to £550 annually versus gas heating. Installation costs range from £24,000 to £49,000, but the UK government offers up to £7,500 through the Boiler Upgrade Scheme plus 0% VAT support.
