Answer: A 6-8 kW horizontal ground source heat pump system usually costs around £12,000 to £15,500 to install. A larger 12kW horizontal ground source heat pump system would cost around £24,000 to install. Vertical ground source heat pumps are more expensive due to the drilling of boreholes, so the equivalent 12kW system would cost around £36,000 to install.

The cost of a ground source heat pump (GSHP)

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 Boiler Upgrade Scheme offers £6,000 towards the cost of installing a system. In Scotland, the Home Energy Scotland Loan offers fantastic financial help in the form of low, or no, interest loans and substantial cash-back incentives for installing with energy efficiency measures and heat pumps.

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

Starting at the smaller end of typical IMS Heat Pumps 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 around £12,000 to £15,000 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 around £24,000 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 £5 to £11 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.

The cost of vertical ground source heat pumps

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 £40 to £65 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 £6,500 per 100m borehole, although this varies and often doesn’t include mobilisation costs. Typically, each borehole will contribute approx. 4kW-5kW 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 £6,000 per borehole. As already stated, for the installation of a 12kW vertical ground source heat pump, you will need three boreholes. This adds up to £18,000 + possible ancillary costs for the drilling alone, which contributes to a £35,000+ installation overall.

Horizontal systems are always cheaper to install. Of course, these costs are all estimates and depend on your individual project!

For more information about installing a heat pump in your property, contact IMS Heat Pumps now.