Ground Source Heat Pump Costs in Scotland (2022) – Explained

One of the first questions from homeowners across Scotland who are considering installing a ground source heat pump is obviously how much does it cost?

We’ve tried to be as transparent and close to the approximate costs.

Here’s a breakdown of the installation cost of a typical ground source heat pump installation:

• GSHP equipment cost for plant room: £12000-13000 (manufacturer prices can vary)
• GSHP borehole cost: £6800 – £7500 per borehole
• GSHP trenches dig & refill cost: £5000 – £6000
• GSHP plant room pipework & fittings cost: £3000 – £4000
• GSHP installation and commissioning cost: £6000 – £7000

Bringing the total anywhere between £25,000 – £40,000

Unlike air-source heat pump systems, which are relatively straightforward to install and determine the installation cost. When it comes to Ground source heat pumps, the installation cost can vary on various factors. Such as is it going to be horizontal trenches or boreholes that will be used to extract heat from the ground.

If it’s horizontal trenches, the installation costs will be less than a borehole system.

In summary:

• A typical ground source heat pump costs with horizontal trenches can be anywhere between £25-30k. These costs will vary depending on the ground condition and the length of the heat collector pipe, also known as ground loops, required to meet the heat load of the house.

• A typical ground source heat pump costs with boreholes can cost anywhere between £35-40k. These costs will vary depending on the ground condition and the length of the heat collector pipe, also known as ground loops, required to meet the heat load of the house.

How can I save money during the installation of my GSHP?

You can save money by clearing up the plant room/ garage or store wherever the GSHP will be installed.

A lot of our customers choose to hire a local digger driver themselves if they’re going with the horizontal ground loop system because it often works out less expensive as we have costs for plant mobilisation etc and our digger driver will charge more if they are working away from home.

Additional expenses such as accommodation and travel expenses have to be accounted for. Getting a local digger driver also means it’s better from an environmental point of view ad provides work for local businesses.

Grants

The UK scheme of domestic RHI came to an end on 31st March 2022.

However, in Scotland homeowners can still apply for a Scottish government grant of up to £8000 and an 0% loan of around £2000 towards the installation cost so £10,000 in total can be claimed if you’re wanting to install air or ground source heat pump.

In England and Wales, homeowners can apply for a £5000 grant to install air source and ground source heat pumps.

Find out more information on our Scotland Heat Pump Grants page.

Running & Maintenance Costs

GSHP running costs in Scotland will vary on the size & insulation levels of your property.

But at present, this is the cheapest form of heating available compared to all the options in the market.

How Much Land Do I Need for a Ground Source Heat Pump?

If you have some land available, then installing a ground source heat pump is one of the best and most cost-effective ways to install the system.

We’ve installed GSHP for farms, holiday lets, and the hospitality sector. When we say “some land available,” we do not mean a garden or even a large garden; it has to be a clear site with no trees in the middle or throughout the land.

The minimum size of ground required for installing ground loops for a 4-5 bedroom house will be between 400-800 sqm depending on ground conditions.

If the ground is sandy, then we’ll need more ground loop, but if the ground is a mixture of wet clay etc then we’ll need less ground loop.

This land area will accommodate a maximum of around 4 x 100meter long trenches which means we’ll be able to lay 800meters of ground loop.

Ground Source Heat Pump Costs Scotland: Boreholes & Trenches

How many boreholes do you need if you want to install a ground source heat pump?

How many boreholes and how deep the boreholes need to be is determined by the room-by-room heat loss calculations of your property and the size of the heat pump itself. To give you a rough idea we would need to aim to achieve a minimum thermal conductivity of 20-25 Watts per metre.

Depending on the local geology we can achieve thermal conductivity of as high as 66-71 watts per metre. As part of our assessment along with room by room heat loss calculations, we would initially get our drilling contractors to carry out a desktop assessment to determine the local geology and the likelihood of what wattage can be extracted from the ground.

How long or how many years can boreholes keep producing energy for the heat pump to run?

Part of our assessment when sizing the boreholes is to take into account the total annual FLEQ run hours required to heat the property every year to a comfortable temperature and our aim is to guarantee that the boreholes will be live for the next 20 years.

How far can the borehole be from the house?

The boreholes can be dug as close as 3 metres from the house. This should not affect the foundations of the property but if you’re aware of something then it’s best to get it checked at the survey stage.

The boreholes have to be a minimum of 7-8 metres away from the closest borehole to allow for sufficient thermal conductivity in the years to come.

How many trenches will I need when installing a ground source heat pump?

Similar to boreholes the number & length of trenches required are determined by the room by room heat loss calculations of your property and the size of the heat pump itself.

The length of ground loops required is determined by the ground condition for e.g. if the area has more dry sand then you’ll need longer ground loops as dry sand has very low thermal conductivity whereas on the other hand water-saturated clay & silt has much higher & better thermal conductivity.

Land that is sloping, well-drained, and southerly facing additional benefits. 

Can I use the land for growing vegetables or use it for grazing after the ground loops have been installed?

Yes, this is not a problem at all you can use the land above for plants and vegetation.

The fact that ground loops are well below the frost level won’t affect the growth of vegetation. 

How deep do you need to dig the trenches if installing a horizontal ground loop system for ground source heat pump?

The minimum trench depth required is 1.3 metres and 1 metre wide, this can be altered slightly to suit the layout of the land available and can only be determined during a site survey.

Final thoughts

If you’re looking to reduce your heating bills, wanting to replace your old inefficient gas, oil, or LPG boiler then an air or ground heat pump should definitely be an option that you have taken into account, and with the highly experienced team at Heat Pumps Scotland, you can be sure that you will get the best possible service and advice.

We provide installation service for the whole of Scotland and the islands.

If heat pumps are not the right technology for you then we will let you know but to find this out you’ll need to give us a call or send us an email.