Ground source heat pumps: How do they work?
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Last updated: 02 July 2021
Most homes around the UK are heated by boilers, but there may be a greener and cheaper alternative that could be suitable for you. Ground Source Heat Pumps could provide a cost-efficient solution to boilers as gas prices rise. Our useful guide can you decide if a ground source heat pump is right for your home, and whether you can save money in the process.
What is a ground source heat pump?
A ground source heat pump is a heating system that uses pipes underground to harness natural heat by pumping water through them. The water is heated up naturally underground and then pumped through your central heating to heat your radiators, underfloor heating and your hot water. It works in a similar way to a boiler, the only difference being that the source of the heat is ambient heat from the ground, rather than heat generated from burning fuel.
How do ground source heat pumps work?
Ground source heat pump systems are made up of a network of underground water pipes in loops outside your home. These are attached to a heat pump that sits at ground level. The loop of pipes has to be buried in land that you own, most commonly in your garden, so you have to make sure you have enough space outside your home. The length of the ground loop depends on the size of your home; the longer the loop, the more heat that will be generated, but also the more space is needed. It’s also possible in some cases to drill a vertical borehole if you do not have that much garden space.
A mixture of water and anti-freeze travels through the pipes absorbing natural heat stored underground. This mixture is then compressed through a heat exchanger which extracts the heat for transfer to your home.
What are the pros and cons of a ground source heat pump?
Ground source heat pumps are considered to be a greener, cheaper way to generate heat for your home. Here is a look at the various benefits that ground source heat pumps can provide:
- Lower bills – by cutting out the need for gas you can lower your energy bills significantly, especially if you are on a cheap electricity tariff.
- Government incentives – you can get financial help towards the cost of a pump through the Renewable Heat Incentive (RHI). For a four-bedroom household you could get payments of around £2,500 a year.
- Greener home – ground source heat pumps generate less CO2 than normal heating systems. If you get your electricity from a renewable source, then your home will be zero-carbon!
- Minimal maintenance – once installed, ground source heat pumps require very little maintenance, which means you won’t have to worry as much about your heating system not working.
- Energy efficient – although you need electricity to power the pump, ground source heat pumps are extremely efficient when it comes to converting electricity into heat.
There are some disadvantages to ground source heat pumps however, and these include:
- Expensive installation – installing a ground source heat pump typically costs between £10,000 and £18,000 depending on the size of your home and the system required.
- Construction time – the required groundworks to dig an area for the pipes can be expensive and disruptive. You may also need planning permission, depending on where you live.
- Restrictive requirements – a lot of properties are not suitable for ground source heat pumps. This may be because they have no outside land, or because the system will not work efficiently in your home.
How much do they cost?
As mentioned, ground source heat pumps typically cost between £10,000 and £18,000 to install. This number is affected by the size of your home, as well as the groundwork needed to lay the pipes.
You also need to consider the running costs. Maintenance costs will be low as very little maintenance is needed with these systems. It’s likely that your general running costs will be lower than before. Switching from gas heating to a ground source heat pump system could save you over £500 per year. A lot is dependent on your electricity deal, as the higher your tariff, the higher the cost of running your ground source heat pump system will be. Make sure you look into whether you are eligible for the government’s Renewable Heat Incentive (RHI) scheme, as this could help you to cover the installation costs of your system.