A ground source heat pump (GSHP) also known as a geothermal pump, harvests solar heat absorbed by the ground. At present, there are two types of collector pipe loop, horizontal or vertical. Usually, vertical collectors go down to as much as 100m or more, depending on the geology of the area and how much heat you require. Alternatively, a horizontal collector loop sits in trenches about 1.5m deep.
Usually, the cost of a ground source heat pump installation will be more expensive than other heating methods. Moreover, a typical GSHP installation costs between £14,000 and £20,000. But, in the long term, ground source heating is a much more efficient heat harvester than air–source heat pumps, and much cheaper than oil and gas.
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Why would you want one?
Although it’s expensive to install, GSHPs have many benefits.
- It will lower your heating bills, especially if you’re replacing electric heating. However, you’ll still use a small amount of electricity for the pump. But, this isn’t anywhere near what you’d use for heating.
- As long as it’s not for commercial premises, the UK government’s Renewable Heat Incentive (RHI) could provide an income. However, there is a separate scheme for non-domestic installations.
- Depending on the fuel you previously used, a GSHP might reduce carbon emissions.
- You won’t need any fuel deliveries.
- A GSHP needs minimal maintenance.
- They are more energy–efficient than most other forms of heating.
If you live in a regular 3 bedroom house the ground source heat pump purchase and installation costs will be between £16,000 and £20,000. On top of this, you must include the groundwork involved with the installation. If you choose the horizontal pipe loop, it’ll cost about £4,000. Whereas, for a vertical loop, it’ll cost about £9,000. Don’t forget, you’ll also need larger radiators, or better still, install underfloor heating to optimise the harvested heat. And, both these will add to the total costs.
But, how much do you reckon you can save by changing from your old electric heating to GSHP? Well, let’s assume you live in England, Wales or Scotland and your home is fully insulated. Well, according to the Energy Saving Trust you’ll save from £1,000 to £1,100 per year on your fuel bill and between 3,300 to 3,600kgs of carbon dioxide emissions every year.
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Main Topics
How Much Does a Ground Source Heat Pump Cost?
Before we start on this, let’s say a word or two about who you’re going to ask to install your GSHP. A trade body, The Ground Source Heat Pump Association has members in the ground pump installation, manufacturing and retailing industries, as well as links to associated industries’ trade associations. If you deal with Association members you can be sure of reputable business dealings and high installation standards.
The initial costs depend on how much heat you need for the size of a house, size of the pump and whether your collector will be horizontal or vertical.
No. of rooms Heat pump purchase price & installation cost
2 £16,000
4 £21,000
6 £32,000
7 £42,000
On top of this, you’ll have:
Running costs
GSHPs need very little energy to run. For example, a typical 4 bedroom house needs about 11,000kWh of energy for heating and 4,000kWh for hot water. Assume a Seasonal Coefficient of Performance (SCoP) of 4.5. So, the house will need:
3,334kWh of electricity to run the equipment.
Now, assume the cost of electricity to be about £0.15/kWh, and this gives 3,334 X 0.15=500.
Therefore, the cost to run a typical GSHP will be about £500, compared to the running costs of £890 for a typical gas boiler.
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And maintenance costs
A GSHP requires very little maintenance. The system is entirely enclosed and sealed so you’ll not need extensive maintenance apart from an annual service. This makes sure that things haven’t started to go downhill. A properly installed GSHP has an estimated lifespan of about 20 to 30 years. Either you or a qualified engineer can do a simple annual check, but it needs a service every 3 or 4 years done by an engineer.
If you need someone to look at a problem with your GSHP, you must contact someone fully trained and competent to work on your equipment. The technician or engineer must be on the UK government’s F Gas register. This proves, they’re certificated to work on refrigeration gases under the Fluorinated Greenhouse Gases Regulations 2009.
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Installation Cost & Process
A typical GSHP collector pumps a mixture of water and antifreeze around a ground loop which absorbs the heat from the ground. The collector pipes can be straight, or more commonly are looped. The cost of installation depends on which collector loop you use. For a typical house, you can install the collector horizontally in two trenches about 1.5m deep and 30 to 40m long. Alternatively, a vertical collector uses a borehole to house the loop and will be anything between 15m and 100m deep depending on your geology and the size of the system. Whichever one you use, it’s important to have a professional survey done to decide which is the best for your circumstances.
You need an installer who is fully qualified and belongs to the Microgeneration Scheme (MCS) if you intend applying for funding from the RHI.
Groundwork prices
Prices for borehole drilling vary depending on the service provider, type of geology and the depth of the borehole. Most drilling companies don’t publish their daily rates, preferring to quote on a job by job basis. However, to give you a rough idea of cost, the cost of drilling a typical water well borehole, about 45m deep will be about £8,600. Whereas, a hole of 75m will cost about £11,600, and 120m will cost about £15,000. The project will require specialist drilling equipment and trained technicians, and probably take 2 to 3 days. Although these boreholes aren’t for the same purpose, they give you an idea of how much you’ll pay. Alternatively, a trench is much cheaper to dig. You only need a JCB and somewhere to temporarily put the soil.
The following table shows typical groundwork charges for installing horizontal and vertical collector loops:
No. of rooms Horizontal collector loop groundwork Vertical collector loop groundwork
2 £3,000 £6,000
4 £5,000 £13,000
6 £8,000 £20,000
7 £12,000 £30,000
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Ground Source Heat Pump Cost Components
Many different factors will determine the final cost of your GSHP installation.
- Do you intend applying for financial help from the Renewable Heat Incentive?
- How big is your home? A large home will need a larger heating system.
- Is your home completely insulated and draught-proof? GSHP produces less heat than conventional boilers and takes longer to heat up so it’s easier to lose heat if you have poor insulation.
- A GSHP requires larger radiators or even better, underfloor heating to make full use of its heat. If you have to install these, it will add to the expense.
- If you are doing major renovations or constructing a new build, you can save money by installing the heating system during building.
- It’s better to install underfloor heating rather than just change the radiators.
- The size of your garden will determine what type of collector loop you should have. You can only use a horizontal collector loop if you have a large garden. And, you also need access for drilling or digging equipment.
- What type of geology do you have where you live? This will also determine whether you use a vertical or horizontal collector too.
- Don’t rely on the GSHP to supply your hot water, as the temperature rarely gets above 50°C. Instead, have solar water heating to boost this. GSHPs are much more efficient if they heat the central heating system alone.
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UK Grants & Schemes
The United Kingdom has a government–sponsored scheme called the Renewable Heat Incentive (RHI). It provides financial help for owners of renewable heating systems and is spread over 7 years. Unfortunately, Northern Ireland no longer provides the scheme, so it’s only England, Wales and Scotland.
To be eligible for the RHI, you must use technologies listed as a Microgeneration Certification Scheme (MCS) certified product. When applying for the RHI financial support you have to provide an MCS certificate to prove you have suitable technology. You can look on the MCS website to find an authorised supplier and installer. But, if you find someone else to install the boiler, they must be accredited under EN 45011 or EN ISO/IEC 17065:2012 for Ofgem to approve them.
Once your MCS approved GSHP is up and running, you’ll receive quarterly payments from the UK government for the following 7 years, based on how much renewable heat you produce.
How Do Ground Source Heat Pumps Work?
We’ve already spoken about the pipes installed into the ground, so let’s move on from there.
GSHPs harvest the heat in the earth from two sources.
- If you use a horizontal collector loop, the warmth comes from the sun absorbed into the ground. Even in winter when the ground is frozen solid, the ground temperature below 1.5m deep remains fairly constant and is the same all the year-round.
- If you use a vertical collector loop, you harvest the sun’s heat in the same way as the horizontal collector. But, depending on the geology, you can also harvest the heat from radioactive minerals within the underlying granite and other igneous rocks.
A pump moves a mixture of water and antifreeze around the pipes, which absorbs the heat. When the warm liquid arrives back at the pump, it uses expansion and compression heat exchanging technology to give up its heat.
The total amount of energy harvested depends on the length of the piping loop, and trenches or the depth of the borehole. Together with, the thermal capacity of the local soil. For example, clay soil holds more heat energy compared to sand.
To get the most out of your GSHP, the installer will carry out a site investigation to determine the geology, before designing the correct length of pipe and size of the heat pump.
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Planning Permission & Building Regulations
Usually, a GSHP is classed as a ‘permitted development’. Therefore, you won’t need Planning Permission unless you live in a listed building or a conservation area. In that case, contact your local authority who can advise you of your options.
Installation of a GSHP must comply with the Building Regulations. Choose an installer who knows what they’re doing and belongs to the Microgeneration Certification Scheme or a relevant Competent Person Scheme.
FAQs
How efficient is a ground source heat pump?
A typical GSHP has an efficiency of about 400%. This means that if the pump uses 1kW of electricity to power the system, it collects about 4kW of heat from the ground.
How long does a ground source heat pump last?
A well made and properly installed GSHP will last for about 25 to 30 years. This is about 10 years more than a typical combustion boiler. Also, the ground heat exchanger is expected to last for more than 100 years.
What are the disadvantages of ground source heat pumps?
The main disadvantages of installing a GSHP are:
- They are very expensive to install.
- They are most efficient if you have an underfloor heating system.
- The installation contractors will significantly disrupt your garden.
Are ground source heat pumps noisy?
GSHPs produce hardly any noise at all. Furthermore, they don’t combust so won’t produce any noise from the environment. And, they don’t need a fan. In fact, the only moving parts are pumps and they can easily be placed indoors. Usually, a typical ground source heat pump makes approximately 40 to 50dB of noise. So, compare this with a quiet library at 30 to 40dB and a dishwasher at 50 to 60dB.
How deep does a ground source heat pump?
This depends on whether you install horizontal or vertical collector loops.
For a horizontal collector system, the pipes are laid in trenches about 1.5 to 2m deep. An average home of about 150m2 requires a pipework area of between 300 and 700m2.
Alternatively, a vertical collector loop needs a borehole of between 45 and 100m deep. Sometimes, even deeper.
Do ground source heat pumps work in winter?
In winter the ground is warmer than the air. While, in the summer, the opposite is true. However, below about 1.5m metres, the ground temperature remains fairly constant all year. Therefore, GSHPs are very efficient in winter months, unlike an air source heat pump.
Get Competitive Quotes
Although ground source heat pumps prices are more than any other renewable heat source, they are probably one of the most efficient renewable energy sources. So, if you can afford to pay the installation charges, you will have a very low running cost heating system that’s good on carbon dioxide emissions too. Complete the form on this page and you’ll receive quotes from 2 to 3 certified local installation professionals.
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we have a chalk mine in the back garden about 200 ft deep. with tunnels running from the shaft. I wonder if a pump could be installed down there