Ground Source Heat Pumps 

Frequently Asked Questions

What is a ground source heat pump and how does it work? 

A ground source heat pump is a renewable heating system that transfers natural heat from the ground into your home. It works by circulating a special fluid through a network of pipes buried underground. These pipes absorb heat from the earth, which maintains a relatively stable temperature throughout the year, typically between 8°C and 12°C in the UK. The absorbed heat is then compressed and used to provide heating and hot water. Because the ground constantly renews this energy, ground source heat pumps offer a reliable and highly efficient way to heat your home all year round.

Is a ground source heat pump suitable for the UK climate?

Yes, ground source heat pumps are particularly well-suited to the UK climate. The relatively mild winters and consistent ground temperatures in the South West mean that the system can perform efficiently throughout the year. Unlike air source systems, ground source heat pumps are not affected by changes in air temperature. This makes them an especially stable and dependable option for rural or off-grid properties, where connection to gas mains may not be available or desirable.

How much does a ground source heat pump cost to install?

The cost of installing a ground source heat pump typically ranges from £14,000 to £24,000. This depends on several factors, including the size of the property, the type of ground available, and the method used to extract heat. For example, systems using slinkies or horizontal loops are usually less expensive than borehole installations, which require deep vertical drilling. While the upfront investment is higher than some other heating systems, the long-term savings and available government funding can make it a very cost-effective choice over time.

What support is available through the Boiler Upgrade Scheme?

The Boiler Upgrade Scheme offers a government grant of £7,500 to help with the upfront cost of installing a ground source heat pump. Funding is available to most homeowners and landlords in England and Wales, provided the property has a valid Energy Performance Certificate (EPC) and no outstanding recommendations for loft or cavity wall insulation. Evergreen is a registered installer under the scheme and will manage the application process for you, ensuring that all eligibility criteria are met and that you receive the full amount you’re entitled to.

What’s the difference between a closed loop and an open loop system?

A closed-loop system uses a sealed network of pipes that circulate fluid underground, absorbing heat from the surrounding soil or water. These can be installed horizontally in trenches (known as slinkies), vertically in boreholes, or submerged in water sources like ponds. An open loop system, by contrast, draws water from a river, lake, or well and passes it through a heat exchanger before returning it to the source. Both systems can be highly efficient, but closed-loop systems are more commonly used in residential settings due to their predictability and lower environmental impact.

How much space do I need for a ground source heat pump?

The amount of space required depends on the type of ground array installed. Horizontal loop systems need a fair amount of land; typically a garden or field area, where the pipes can be buried at a shallow depth. Borehole systems, on the other hand, need far less surface area but require deeper drilling, which can be more costly. Pond or water-based systems require access to a suitable body of water. Evergreen will carry out a detailed site assessment to determine the most appropriate solution based on your property and land conditions.

What are the running costs compared to other heating systems?

Ground source heat pumps are among the most efficient heating systems available. They typically produce around four units of heat for every one unit of electricity used. As a result, running costs are generally lower than oil, LPG, or direct electric systems. If combined with a solar PV system, the electricity needed to run the pump can be partly or fully generated on site, further reducing costs. Over time, the lower running costs can help offset the higher installation price and provide a strong return on investment.

Do ground source heat pumps need regular maintenance?

Ground source heat pumps are designed to be low-maintenance. Once installed, the buried pipework can last for over 50 years with no need for replacement. The main heat pump unit, usually located indoors, should be serviced annually to check filters, pressures, and controls. Routine checks help keep the system running efficiently and extend its lifespan. Evergreen offers ongoing servicing and support to ensure your system continues to perform reliably for many years after installation.

How long does a ground source heat pump last?

With proper maintenance, the main heat pump unit typically lasts between 20 and 25 years. The ground loop system – the network of pipes that collects heat – can last for over 50 years. Because there are fewer moving parts compared to traditional boilers, ground source systems tend to be more reliable and less prone to breakdowns. Investing in a quality installation and regular servicing is the best way to ensure long-term performance and efficiency.

Do I need planning permission for a ground source heat pump?

In most residential cases, ground source heat pump installations fall under permitted development rights and do not require planning permission. However, if your property is listed, located in a conservation area, or the installation involves a significant water source or borehole, you may need to apply for consent. Evergreen’s team is experienced in managing these requirements and can provide clear guidance and support with any planning or environmental permissions that might be needed.

Can a ground source heat pump heat my entire home?

Yes, a properly designed ground source heat pump system can comfortably heat your entire home and provide all your hot water. It works with radiators, underfloor heating, or a combination of both. The key is ensuring the system is correctly sized to match the heating demand of the property. Evergreen carries out a full heat-loss assessment for every installation, ensuring that your system is able to meet the specific energy needs of your home.

Why choose Evergreen for your ground source heat pump?

Evergreen has been installing renewable heating systems across Dorset, Devon, and Somerset since 2011. As a trusted installer of Kensa Heat Pumps – a British manufacturer known for their quality and performance – Evergreen delivers a reliable, local service backed by technical expertise. All installations are handled in-house by experienced, MCS-certified engineers, with no subcontractors involved, (except for ground works or borehole drilling). From site surveys and design to installation and aftercare, Evergreen offers a complete service and ongoing support for homeowners looking to make a long-term investment in sustainable heating.

Can a ground source heat pump be retrofitted into an older home?

Yes, ground source heat pumps can be installed in older properties, provided certain conditions are met. The key consideration is the energy efficiency of the building, particularly insulation levels. A home that retains heat well will allow the system to operate efficiently and maintain comfort. If your home has solid walls or minimal insulation, upgrades may be recommended before installation. Evergreen will assess the property and suggest any necessary improvements to ensure the system performs effectively in an older building.

How disruptive is the installation process?

Installing a ground source heat pump is more involved than other systems, particularly when it comes to the groundworks. If you opt for a horizontal system using slinkies, excavation of trenches is required. Borehole systems involve drilling, which takes up less space but requires specialist equipment. The internal work is similar to that of other heating systems, involving installation of a heat pump unit, hot water cylinder, and system controls. Evergreen takes care to minimise disruption and works to an agreed schedule, keeping you informed throughout the process.

What happens if my land isn’t suitable for a standard loop system?

If your property doesn’t have enough space for a horizontal ground loop, there are still viable options available. Boreholes can be drilled vertically, often to depths of around 100 metres, which require much less surface area and are ideal for smaller plots. If you have access to a pond, lake, or river, a water-source system may be possible. Evergreen has extensive experience in designing and installing alternative ground loop configurations and will recommend the best approach based on your site conditions and budget.

Got another question? Get in touch