What are ground source heat pumps?

Most UK homes use a boiler for heating and hot water. While this technology has become increasingly efficient over the years, ground source heat pumps are an even more eco-friendly and cost-effective solution. Here, we’ll look at how a pump works and whether or not it could save you money.

Hot water tap heated from ground source heat pump

In this guide:

  • What is a ground source heat pump?

  • How do ground source heat pumps work?

  • Can I install a ground source heat pump at my property?

  • How much does a ground source heat pump cost?

  • Ground source heat pump prices: maintenance costs

  • Is ground source heating right for me?

  • Ground source heat pump reviews: the verdict

What is a ground source heat pump?

Ground source heat pumps use underground pipes that extract heat from the earth. This is then used within your home’s heating and hot water systems. A mixture of water and antifreeze is pumped down into the ground system and back out again to provide heat. 

A ground source heat pump includes an evaporator, compressor, and condenser to heat the water and pipe it into your home’s heating system. Because underground heat stays at a consistent temperature year-round, you can use a ground source heat pump throughout the year. 

How do ground source heat pumps work?

Ground source heat pump installation involves burying a loop of pipe (fittingly called a ground loop) underneath the ground. Fluid containing both water and antifreeze flows through the ground loop, absorbing ground heat at low temperatures. As the warm fluid passes through the pump’s compressor, its temperature continues to increase. From there it’s used to heat the water for a household’s heating and hot water systems. Afterwards, the cooled fluid passes back through the ground loop to absorb more ground heat and repeat the journey. 

The ground loop can be installed horizontally in a trench, or vertically in a borehole. The size and space needed will depend on several factors, including your local geography and home heating requirements. 

A greener source of heating

This type of system is an eco-friendly alternative to other types of heating because it uses less carbon than electric heating systems or gas. Ground source heat pumps are considered renewable energy because they generate their heating from a renewable source. This means you might be entitled for payment to offset installation costs through the government’s Renewable Heat Incentive scheme. 

Can I install a ground source heat pump at my property?

Although domestic ground source heat pumps are generally allowed throughout the UK, some authorities do require planning permission. It’s a good idea to check with your local authority before you arrange your installation. 

Not all properties will be suitable for this type of heating. A ground source heat pump requires a lot more space than a standard boiler system, with most of it installed underground. Horizontal ground loops are laid in a trench around 1-2 metres below ground, but require a lot of space, depending on your local conditions and heating requirements. If your garden isn’t large enough, ground loops can be installed vertically in boreholes that extract heat from much deeper underground – typically anywhere from 90 to 160 metres.

A successful installation will depend on your garden’s suitability: its size, soil type (for digging), and accessibility for the digging machinery required. 

You should also consider the fact that ground source heat pumps don’t produce as much heat as traditional gas-fired or electric heating systems. This makes them more suited to well-insulated homes that don’t require as much heat. 

How much does a ground source heat pump cost?

A typical system costs anywhere from £14,000 to £19,000 to install according to the Energy Saving Trust – horizontal systems are cheaper than vertical ones, and your garden’s soil will play a part too. The system is powered by electricity, so running costs will depend on factors such as the size of your home and its level of insulation. While it costs less to run than other heating systems, your annual savings will vary dramatically depending on your current setup – for example, in a well-insulated four-bedroomed detached home, you might save around £1,000 a year switching from an electric heating system, but only £25-30 a year switching from gas. To maximise savings, you need to be sure that the installer uses the optimum settings including placement and insulation.

You should also look to sign up with the Renewable Heat Incentive (RHI) scheme, which sees the government make quarterly payments over a seven-year period based on your consumption to help offset the expensive installation costs.

Ground vs air source heat pump cost

A similar option for improving your heating’s efficiency is the air source heat pump. As their name suggests, these heat pumps absorb heat from the outdoor air. The extracted heat can be used to heat up hot water, radiators, and other parts of the home. Installation is much cheaper: a typical air source heat pump costs between £6,000 and £8,000 to install, depending on your home’s size, location, and household habits. Again, it’s supported by the RHI scheme.

Ground source heat pump prices: maintenance costs

One area you should be well covered is with maintenance. Heat pump systems usually come with a warranty of at least two years, including a workmanship warranty that lasts for up to 10 years. You can also look at extending the warranty for an added fee. 

Most ground source heat pumps work for over 20 years, provided they’re maintained regularly. You can check the system yourself on an annual basis, with a professional engineer coming out to service the system every three to five years. 

According to the Ground Source Heat Pump Association, there’s no need for added safety checks. Routine maintenance requirements are low: a simple check of external pipes, electronics, and water pump to make sure everything’s working smoothly. 

Is ground source heating right for me?

We’ve already touched on the need for a suitable garden for installing a ground source heat pump, but there are a few other considerations. Your home should be well-insulated and draught-proof because this type of heating system produces slightly lower temperatures. This also means you need to leave the system on for longer during the cold winter months.

AdvantagesDisadvantages
Ground source heat pumps are eco-friendly in comparison to gas or coal. Installation costs are quite high and can vary significantly from one property to the next.
You might recoup some of your money through the Renewable Heat Incentive scheme. The installation process will involve digging up your garden.
You might save money on your monthly heating bills. Ground source heat pumps provide a lower heat than other systems, working best with air heating and underfloor systems.
This type of system uses a renewable source of heating, to reduce your carbon footprint.
After installation, ground source heat pumps require very little maintenance.

Ground source heat pump reviews: the verdict

Is a ground source heat pump right for you? It depends on your home’s location and garden suitability. This type of heating system does cost well over £10,000 to install, which is a large upfront cost in comparison to a modern boiler or other renewable heating options. However, it could end up saving you money on your energy bills over time.

Not all heat pumps are the same, so you should also read ground source heat pump reviews carefully both in terms of the systems and installer to find the right fit. 

Cleaner and greener than other systems, ground source heat pumps offer a sustainable energy alternative to gas or coal. Additional ways to keep bills low include insulating your home, installing draught-proofing to windows and doors, and checking to make sure you’re on the best energy tariff

Last updated: 21 December 2020