What is a ground source heat pump (GSHP)?
A ground source heat pump (GSHP) extracts heat from the ground using pipes buried underground, either in the garden or on adjoining land. This can then be used to heat water in radiators and underfloor heating – as well as providing hot water.
How does it work?
The pipes for a GSHP system are most commonly buried horizontally in a trench, about a metre below ground, providing enough space is available to do this. Alternatively, boreholes can be drilled to extract heat from further down.
The way a GSHP works is by circulating a fluid made up of water and antifreeze through a ground loop buried in a garden. The heat from the ground is absorbed at low temperatures by the liquid which then passes through a heat exchanger into the heat pump.
Benefits of using a ground source heat pump
Because the ground temperature is relatively consistent throughout the year there are numerous benefits to using a ground source heat pump heating system:
- Your fuel costs may be reduced, particularly if replacing heat by direct electric, LPG, coal or oil
- You could earn income from the Government’s Renewable Heat Incentive
- Reduced carbon emissions
- Provides hot water and heat for your property
- No need for fuel deliveries
- Reduction in annual maintenance costs
How much does a GSHP cost and save?
GSHPs can be expensive to install initially but they can also offer considerable savings in the long term.
The cost of a ground source heat pump will depend on several factors, such as the property, its location and the ground loop system chosen. A horizontal trench system would cost less to install than a vertical one as boreholes require specialist equipment. However, a ground trench system may not always be feasible as it is dependent on suitable land space and ground conditions.
The average cost of a GSHP pump with installation is estimated at around £18,000 according to installations registered on our job registration system.
The Coefficient of Performance (COP) of your GSHP will determine what you will save on your heating bill. The COP is a measure of the efficiency of the heat pump. For instance, if the GSHP has a COP of 4, then it will output 4kW of heat for every 1kW of electricity consumed by the heat pump.
Extensive excavation work may be required for the installation of a GSHP. Trenches or boreholes will have to be dug for the heat pump loops, which can be buried either horizontally in a shallow channel (between 1m-2m deep), or vertically in a borehole (at a depth ranging from 15m to 120m).
Depending on the local geology, drilling and lining a borehole for the GSHP could cost in the range of £60 to £100 per metre. *1
What to consider?
There are several factors to consider when thinking about having a ground source heat pump installed:
- Although the grounds of your property don’t necessarily need to be large, the land would have to be accessible for specialist digging equipment and suitable for a trench to be dug or borehole drilled.
- Ground source heat pumps work best in a well-insulated property as they generate heat at a lower temperature than traditional boilers.
- If you’re replacing an electricity or coal heating system then a ground source heat pump should deliver significant savings, particularly if the property is well insulated. If you currently use mains gas then switching to a GSHP may not be the best option.
- If you have an underfloor heating or a warm air heating system, rather than radiators, then a ground source heat pump will perform much more efficiently due to the lower temperatures needed.
- If the property that you are installing the ground source heat pump into is a new development then you will be able to reduce the cost of installation by combining it with other building work. The property can also be designed to higher insulation values, making the GSHP more efficient.
It is always advised to check with your local authority to find out whether or not you need planning permission. However, domestic ground source heat pumps are usually allowed as permitted developments.
Find an installation company
You should always choose a reputable installation company to fit your ground source heat pump system. All HIES Accredited Installers are continually vetted in many areas in order to give consumers trust, confidence and peace of mind.Find your nearest HIES installer