A ground source heat pump requires installation underground. It draws energy from the earth so that it can be used to heat or cool your home and heat water.
Before deciding to install a ground source heat pump, it’s important to understand how much space is required for the underground elements of the pump.
Not all homes have enough space to install a ground-based heat pump, so it’s essential to consider this factor when weighing up the pros and cons.
The amount of space required for a ground source heat pump depends on the size of the system and what type of ground source heat array you choose.
The exact amount of space required will differ for each property, making it important to research before committing to installation.
How Does a Ground Source Heat Pump Work?
A ground source heat pump absorbs natural heat from the ground, transferring it into a building so that it can be used to heat the property.
Ground source heat pumps are powered by electricity and use a series of pipes, known as ground collectors, that are laid underground.
Ground collectors can be installed either horizontally or vertically. When installed horizontally, they are buried about 1.5-2 metres underground, while vertical boreholes are typically about 100 metres deep.
A fluid made of water and refrigerant is circulated through the ground collectors.
It absorbs thermal energy and then circulates it back to the heat pump, where a compressor increases the temperature.
A heat exchanger transfers the heat to hot water cylinders and radiators, or perhaps underfloor heating if you choose to install it.
Installing a Ground Source Heat Pump
The installation requires digging underground to install pipes either vertically or horizontally.
Vertical installation can be the better option if you have less space available. Another factor to consider when comparing these two options is the price.
The cost of installing a vertical system is typically higher than installing a horizontal system.
Other factors also affect the cost of installation, including access to the ground, the heat pump you choose, the size of the property, and whether the property is an existing property or a new-build.
Help with covering the costs is available in the form of government grants.
Ideal Land Size for Ground Source Heat Pump
Exactly how much land you will need for a ground source heat pump depends on several factors.
A horizontal system will typically require about 10 metres of trenching for each kW. Between each trench, there should be a space around 5 metres wide.
If the space for a horizontal system isn’t available, then you can also use vertical boreholes. Each borehole requires around 150mm of space, but they may need to go as deep as 60-200m.
There should also be 5-10m of space between each borehole.
Another factor that affects how much space is needed for a ground source heat pump is the heat requirements of the property.
Larger properties will typically require more heat, which means they will need a larger system. Fortunately, larger homes often have more space around them that can be used for this purpose.
You will also need to consider the geology and water table when determining how much space is required and the suitability of the land.
A geotechnical site investigation should be carried out to determine the Coefficient of Performance before a ground source heat pump can be installed.
This will reveal important information such as the thermal properties of the soil, water table level, surface and subsurface temperature, and the flow direction of the groundwater. These factors will influence which type and size of ground collector should be chosen for the property.
Space Requirements for Ground Source Heat Pump
Ground source heat pumps with a horizontal array need a larger amount of space compared to vertical arrays. The general rule is that they require about two and a half times the area of the house in land for there to be enough space for all of the piping.
For example, if the house takes up 1,500 square feet, there will need to be 3,750 square feet of land for the horizontal ground collectors to be installed.
However, it’s also important to take into account the individual heating needs of each property. Requirements can vary depending on how well-insulated the property is.
A more modern or recently modernised property may have a lower heat requirement, while an older home could have a higher demand for heat due to less adequate insulation.
Determining Inside Space Required for a Ground Source Heat Pump
Another important factor to consider is how much space could be required inside a property when installing a ground source heat pump.
The good news is that ground source heat pumps take up little space once they’ve been installed. After installing the underground portion, the pipework can be covered back up so the land can be used as normal. Indoors, you will need a small unit, often about the size of a small fridge.
You will also need a hot water cylinder. This is sometimes integrated with the heat pump unit. Some people place these essentials in a utility room or another dedicated space.
Heat pumps are quiet, making about as much noise as a boiler. However, as they do produce some noise, it’s often preferable to put them in a space away from the general living space, much like you would choose to do with other heating equipment.
Calculating Land Needed Before Installing a Ground Source Heat Pump
Every property has different requirements for land when installing a ground source heat pump. That’s why it’s important to consult with an expert before deciding whether a ground source heat pump is a good fit for your home.
There are several factors to consider to make sure you have enough land available and choose between a vertical or horizontal array.