Answer: A 6-8 kW horizontal ground source heat pump system usually costs around £12,500 to install. A larger 12kW horizontal ground source heat pump system would cost between £15,500-£16,000 to install. Vertical ground source heat pumps are more expensive due to the drilling of boreholes, so the equivalent 12kW system would cost around £30,000 to install.
The cost of installing a ground source heat pump depends on which system is suited to your unique needs. Naturally, larger systems will be more expensive than smaller systems. It also depends on site conditions and the complexity of your project.
The good news is that the Renewable Heat Incentive (RHI) scheme offers long-term return on investment, and the Assignment of Rights (AoR) can cover the initial capital outlay of installing a heat pump. In Scotland, the Home Energy Scotland Loan offers fantastic financial help with energy efficiency and the installation of renewable energy technology.
Starting at the smaller end of typical Smart Renewable Heat projects, we would usually install a 6kW heat pump. The heat pump units has an integrated hot water cylinder with a small horizontal ground loop; usually 250-300 metres in length. This type of system would cost a total of around £12,500 to install.
As the system capacity increases, so do the costs. Larger systems also usually have larger water cylinders. So, a 12kW ground source heat pump with a 750m ground loop and a 300 litre water cylinder would work out at between £15,500 and £16,000 for installation.
For all ground source heat pump installations, you must account for the additional digging costs. This might consist of trenching for horizontal systems, or the drilling of deep boreholes for vertical systems. The cost of this depends on who is doing the work; if you’re lucky enough to have a friendly local farmer nearby with the appropriate equipment, the chances are that your costs will be less than if you hired the plant and labour from professional groundworks contractors.
The rates vary for groundworks contractors between £2 to £5 per metre for digging trenches that are suitable for horizontal system ground loops. As we’ll see, if you opt for a vertical ground source heat pump system which uses deep boreholes, this specialist work demands a much bigger investment. Regardless, you will always need to do local research to determine the exact costs of plant and labour for installing a ground source heat pump.
Let’s say we are installing a 12kW vertical ground source heat pump. What would be the costs associated with installing this system?
Drilling boreholes is an inherently expensive endeavour. First and foremost, you need to hire specialist contractors who use specialist equipment. This equipment needs to be brought onto site with clear access, which is often a challenge in itself and can add complexity to a project.
The cost of drilling boreholes varies, but is usually between £25 to £40 per metre depth. In addition to the drilling, you also have the costs of grouting the pipe and mobilising the plant equipment. A useful guideline is £4,000 to £6,000 per borehole, although this varies. Typically, each borehole will contribute approx 4kW to the system. Therefore, with a 12kW ground source heat pump system, you will likely need to drill three boreholes.
With this in mind, let’s assume that borehole drilling costs £5,000 per borehole (the mid-point within our £4,000 to £6,000 estimate). As already stated, for the installation of a 12kW vertical ground source heat pump, you will need three boreholes. This adds up to £15,000 for the drilling alone, which contributes to a £30,000 installation overall.
Horizontal systems are always cheaper to install. The equivalent 12kW ground source heat pump system with horizontal ground loops would add up to around £17,000 for the installation, in total. Of course, these costs are all estimates and depend on your individual project!
The Renewable Heat Incentive (RHI) scheme will ensure that the return on your investment is good, and utility bill savings are felt immediately. Even for the most expensive ground source heat pump installation, you will get a return on investment. However, the return for larger vertical ground source systems will occur over six or seven years, rather than the three to four years payback that you can expect with a horizontal ground source heat pump.
The quarterly tariff returns via the RHI are higher for ground source heat pumps than they are for air source heat pumps. As these tariffs are regularly revised in line with inflation, it is best that you track the Domestic RHI tariffs here, and the Non-domestic RHI tariffs here. Our experts are able to provide clarity on the tariffs you can expect. If you are in any doubt, please contact us today.
You can see your estimated savings and earnings for installing a ground source heat pump by using our free online calculator. Whilst this will provide you with a good guideline for payback, we encourage you to contact us if you’re thinking of installing a heat pump.
Our experts can provide you with more information about costs, savings, and payback through the Domestic and Non-domestic RHI schemes. We can also help finance your heat pump installation using the Assignment of Rights or Home Energy Scotland Loan.
For more information about installing a heat pump in your property, contact Smart Renewable Heat now.
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