Ground Source Heat Pumps: Explained & Reviewed

Ground Source Heat Pumps: Explained & Reviewed

Ground Source Heat Pumps

A ground source heat pump is a renewable heating system that produces hot water for taps and showers and central heating. In this article, we explain how a ground source heat pump works to give you a better understanding of the technology, the best models on the market (including ground source heat pump reviews), and whether a ground source heat pump is right for your home.

What is a ground source heat pump?

When the sun beams down upon the earth, some of this heat is absorbed by the ground. A ground source heat pump is a renewable, or low-carbon, heating system that heats your home and domestic hot water by extracting this natural heat from the ground around your home.

Ground source heat pump system pushes a mixture of antifreeze and water around loops of pipe (a ground loop) which are buried (either horizontally or vertically) in your garden where they can extract the sun’s heat from the ground.

A heat exchanger then warms the heat to an even higher temperature and passes it to a cylinder in your home to provide hot water for central heating and domestic use.
The ground-loop fluid is then recirculated through the pipes so it can absorb more heat from the ground, and will continue to do so whenever hot water is required.

The temperature beneath the ground stays at a constant temperature all year round, so ground source heat pumps are effective even in winter. Ground source heat pumps need a small amount of electricity to run, but they run on renewable energy and do not produce carbon emissions when operating.

Types of ground source heat pumps

The type of ground source heat pump you need will depend on the size of your home and how much hot water you use. The larger your home and the more hot water you use, the longer your ground loop will need to be so that it has a bigger surface area to absorb heat through. Ground loops can be buried either horizontally about a metre below the surface if you have enough space, or vertically down to a depth of 90-160m if outdoor space is restricted.

A professional ground source heat pump installer will assess your home’s size, outdoor space, and hot water demand to ensure you get the right system for your needs.

Living with a ground source heat pump

It will be no surprise to learn that the heating system of choice in the UK is the gas boiler. Over 80% of UK homes rely on a gas boiler for central heating and we’ve grown accustomed to seeing them in homes. Renewable heating systems, on the other hand, are unfamiliar to most and make up around 2% of heating systems installed in the UK.

As a result, few people know what it’s like to live with a heat pump. And you’ll probably want to know what it will be like before having one installed.

Pros of a ground source heat pump

Installing a ground source heat pump brings lots of benefits reducing your carbon footprint to enjoying potentially lower heating bills. Here are the main pros of a ground source heat pump explained.

Reduce your carbon footprint

Ground source heat pumps are low carbon heating systems that don’t release carbon into the atmosphere as they work to heat the home. This is because they’re taking heat from a renewable source of energy (natural heat from the sun which has been absorbed by the ground) rather than burning fossil fuels.

Potentially lower heating bills

Depending on the heating system you are replacing, you could start enjoying lower heating bills. The biggest difference in heating costs is likely to be found when replacing an electric or coal heating system.

Highly efficient

Ground source heat pumps are incredibly efficient as for every kilowatt-hour of electricity used, it is generating 3-5 times as much heat (depending on the model). This makes ground source heat pumps 300-500% efficient, while gas and oil boilers are unable to convert all of the fuel used into heat with efficiency ratings between 60-93%.

Safe system

A key difference between a ground source heat pump and a boiler is that the heat pump does not burn fuel. This makes it a safer heating system as it does not produce waste gases and there is no risk of a carbon monoxide leak.

Long lasting and low maintenance

Ground source heat pumps don’t need to be replaced for between 20 and 25 years. This is around twice as long as a modern gas boiler. Plus, a professional servicing every 3-5 years will keep them running reliably as opposed to the annual servicing needed for boilers.

Eligible for RHI payments

To encourage more homeowners to turn to renewable heating systems, the government unveiled the Renewable Heat Incentive (RHI). Through the RHI, you can receive quarterly payments over a 7 year period as a reward for the heat generated by the heat pump.

RHI tariffs are paid on a pence per kilowatt-hour of renewable heat generated with the tariff being reviewed on a quarterly basis. As of December 2020, the tariff for ground source heat pumps stands at 21.16p per kilowatt-hour.

No fuel deliveries needed

Unlike oil, LPG, and biomass boilers, ground source heat pumps do not require regular deliveries of fuel or space for fuel storage.

Cons of a ground source heat pump

As with any new and unfamiliar heating system, there are some considerations to make before having a ground source heat pump installed.

High upfront costs

A ground source heat pump is one of the most costly renewable heating systems to install with total costs falling between £14,000-£19,000. Vertical systems are usually more expensive as specialist digging machinery is required to dig the boreholes.

Property must be well insulated

As ground source heat pumps heat to a lower temperature over a longer period of time, it’s important for the property to be very well insulated. Otherwise, the benefit of the heat won’t be felt.

Hot water and radiators may not be as hot

Ground source heat pumps heat water to a lower temperature than boilers which means that the heating may not be as hot. For this reason, they’re most well suited to underfloor heating and large radiators as the bigger surface area allows for the heat to spread around the room more effectively.

Running costs can be costly

To operate, a ground source heat pump needs electricity. And while they can produce 3 to 5 times more energy per kWh of electricity used, electricity is currently an expensive fuel.

According to the Energy Saving Trust, average electricity prices in the UK sit at around 16p/kWh while natural gas is 4.17p/kWh. However, as supplies of natural gas run lower and ‘green’ electricity generation (e.g. solar and wind) increases, the price gap will shrink.

Can be difficult to install

Properties with no outside space will not be able to install a ground source heat pump, and even those which have the outside space may find the installation process disruptive.

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

Installing a typical ground source heat pump system costs around £14,000 to £19,000. This is for the heat pump itself and the installation.

Ground source heat pump installation can vary greatly depending on a number of factors:

  • Complexity of the installation and whether it’s installed vertically or horizontally (vertical installation is more complex and therefore more expensive)
  • Heat pump manufacturer and model
  • The size of the heat pump (the higher your demand for hot water, the more expensive the system is likely to be)
  • Labour rates charged by the installer will vary between companies
  • Whether insulation is required
  • If larger radiators or underfloor heating is required
  • If you need to buy and install a hot water cylinder which is compatible with a ground source heat pump.

As there are so many variables when it comes to having a heat pump installed, it’s highly recommended that you compare quotes.

Getting quotes from at least 3 installers will give you the greatest chance of finding the fairest and most competitive price. Using our simple online form, you can get free quotes from up to 3 installers based near you.

Green Homes Grants for Ground Source Heat Pumps

Until 31st March 2022, you can apply for a government grant to cover two-thirds of the cost of installing a renewable heating system.

The Green Homes Grants scheme gives UK homeowners up to £5,000 (£10,000 for the lowest income households) towards the cost of installing an air source heat pump, ground source heat pump or a solar thermal heating system.

Click here for more information.

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

Ground source heat pumps need electricity to operate which isn’t exactly the cheapest of fuels, particularly when compared to gas and oil. So, while a ground source heat pump may help heating bills to go down, your electricity usage is likely to increase.

Fortunately, ground source heat pumps are highly efficient. While a boiler will never use 100% of the fuel (roughly 7% to 40% of energy is wasted), a ground source heat pump can produce 3 to 5 times as much energy as it uses.

The running costs of an air source heat pump will vary from property to property. Here we explain some of the factors that will impact the running costs of a ground source heat pump.

Fuel prices

Running costs will depend on a number of factors including the size of your home and how well insulated it is. As heat pumps don’t burn fuel, you’re very likely to save money on your heating bills, but the amount of money you will save will depend on the heating system you are replacing. If your old heating system was inefficient, you are more likely to see lower running costs with a new heat pump, as well as a reduction in carbon emissions.

Heating System to be Replaced by Ground Source Heat Pump Potential Annual Savings (£) Potential Annual Carbon Savings (tonnes)
Gas boiler £25-£30 2.5-2.7
Oil boiler £20-£30 3.9-4.2
LPG boiler £530-£570 3.1-3.3
Electric heating £1,000-£1,090 3.6-3.9
Solid fuel heating, e.g. coal £400-£440 9.9-10.6

Figures taken from the Energy Saving Trust based on April 2020 data.

Heat distribution system

Ground source heat pumps work most efficiently with underfloor heating or radiators with a large surface area. This is because they heat water to lower temperatures than boilers, but over a longer period of time. Larger heat distribution systems allow them to continue heating the property effectively while maintaining highly efficient performance.

Demand for domestic hot water

The efficiency of the heat pump could be hampered if it also has to work to provide domestic hot water. For a heat pump to deliver hot water it must be installed alongside a hot water cylinder. To keep the efficiency of the ground source heat pump as high as possible, you may want to consider solar thermal heating.

Using heating controls effectively

Learning how to control the heat pump system so you can get the most out of it should mean that you can set the thermostat lower and still feel comfortable. Your installer should explain to you how to control the system so you can use it most effectively.

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Best ground source heat pump reviews

As the importance of embracing renewable heating systems becomes more widely accepted, an increasing number of manufacturers are bringing their own ground source heat pump models to market. While there aren’t as many ground source heat pump manufacturers as boiler manufacturers, there’s still a few to compare. And as part of those comparisons, consider best ground source heat pump reviews.

To find the best ground source heat pump for your home, it’s important to consider the following:

  • Output rating
  • Dimensions of the unit
  • Length of the warranty period
  • Efficiency rating
  • Potential cost
  • If it’s Microgeneration Certification Scheme (MCS) certified – required for Renewable Heat Incentive eligibility

Best ground source heat pumps and prices

In the table below, we’ve compared key information about the best ground source heat pump models side-by-side.

Manufacturer Model Available Outputs (kW) ErP Energy Efficiency Rating Potential Price
Vaillant geoTHERM 22, 30, 38, 46 A++ £8,000 – £12,000
Viessman Vitocal 222-G 6.1 – 10.0 A++ £6,000 – £7,500
Nibe Nibe F1145 5 – 17 A+++(17kW – A++) £9,000 – £10,000
Kensa Evo 7, 9, 13, 17 A++ £8,000 – £12,000
Worcester-Bosch Greenstore 6 System 6, 7, 9, 11 A+ £4,500 – £8,000

The above prices are estimates but many ground source heat pumps tend to cost £8,000 to £12,000.

Nibe ground source heat pumps

NIBE Ground Source Heat Pumps
A Nibe heat pump could potentially lower your energy bills by as much as 75%. This is thanks to minimal electricity being needed to power the heat pump during operation. Nibe ground source heat pumps are split into 2 ranges: the F Series and the more recent S Series.

Vaillant ground source heat pumps

Vaillant Ground Source Heat Pumps
The most popular Vaillant ground source heat pumps are in the geoTHERM range. However, they also manufacture a diverse range of flexoTHERM multi source heat pumps which can be adapted to take heat from the air or water as well as the ground. These heat pumps are amongst the most quiet during operation and have been awarded Quiet Mark accreditation as a result.

Viessmann ground source heat pumps

Viessmann ground source heat pumps
Viessmann have an extensive range of ground source heat pumps to choose between with outputs from 5.6 kW all the way up to 96.1 kW. Their Vitocal range of heat pumps offer a number of benefits for new builds, semi-detached, detached homes and larger residential properties. If you’re looking for a heat pump that can meet your domestic hot water demands then the Vitocal 222-G has an integral hot water cylinder.

Mitsubishi ground source heat pumps

Mitsubishi Ground Source Heat Pumps
Mitsubishi Ecodan Monobloc heat pumps can take heat from the ground or a water supply, such as a lake. These are powerful models with outputs of 45 kW and 60 kW that can be installed as single modules or stacked together to increase the power output (up to 960 kW).
The system delivers water flow temperatures of up to 65°C and is MCS certified which means that it’s eligible for the Renewable Heat Incentive.

Worcester Bosch ground source heat pumps

Worcester Bosch Ground Source Heat Pumps
Worcester Bosch ground source heat pumps are available as either combination (combi) or system models. All models in the combi range have an integrated hot water cylinder (185 litres) for domestic hot water storage. Meanwhile, the system range of heat pumps require you to have a separate hot water cylinder installed. It’s important to note that this hot water cylinder must be heat pump compatible.

Kensa ground source heat pumps

Kensa Ground Source Heat Pumps
Kensa offers a range of ground source heat pumps ranging from 3 kW up to 30 kW are: Evo, Shoebox and Twin Compact. All of Kensa heat pump ranges are highly efficient, including a 5-year warranty of 5 years. A key benefit of all single-phase Kensa heat pumps are the electrical ‘soft starts’ which ensures that energy consumption is kept to a minimum during start-up.

Click here for more information on the Best Ground Source Heat Pumps.

Renewable Heat Incentive

One of the benefits of installing a renewable heating system is that you could receive payments through the Renewable Heat Incentive. The RHI is a government scheme designed to encourage homeowners to turn to renewable heating.

Through the RHI, you could receive quarterly payments over a 7 year period. Tariffs vary depending on the heating system being used and are reevaluated by Ofgem each quarter.

Successful applications submitted between now and 31st March 2021 will receive the tariffs in the table below.

Renewable Heating System

RHI Tariff
Air source heat pump 10.85p/kWh
Ground source heat pump 6.97p/kWh
Biomass 21.16p/kWh
Solar thermal 21.36p/kWh

Note: The Renewable Heat Incentive is set to be replaced by the Clean Homes Grant from 2022.

Get quotes for a ground source heat pump

As we’ve seen, heating your home with a ground source heat pump can lower your heating bills and earn you RHI payments. You’ll also be lowering your carbon footprint. So, there are numerous reasons why you’d want to install a ground source heat pump.

The only potential sticking point are the installation costs. With several variables that could have an impact on the amount you end up paying, comparing quotes from at least 3 installers is highly recommended.

We can connect you with up to 3 local heat pump installers who will each provide a free no-obligation quote. Once you have your quotes, you can then compare them. This will give you the greatest chance of finding the most competitive price from the most suitable installer.

To get your free quotes, all you need to do is complete our simple online form.

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