A ground source heat pump is a low carbon heating system that utilises heat from the ground or water to heat your home and provide hot water.
Underground ambient heat is collected through pipework and compressed to provide higher temperatures in your home. Ground source heat pumps can provide all your heating and hot water needs for your home.
Ground source heat pumps can offer the same features as a conventional boiler, so can heat hot water and radiators in your home, but instead of burning fossil fuels, they use heat already available from the ground.
Due to the ground temperature remaining at a constant 10-12 degrees year round they don’t have to work as hard as air source heat pumps to create heat in the cold weather.
Ground source heat pumps can also offer the added benefit of providing a cooling function in your home.
Geothermal pumps use electricity to generate heat and are considered energy efficient as they use less electricity than equivalent fossil fuel boiler would require to produce the same amount of heat.
Here is what geothermal heating is.
How do you install a ground source heat pump?
Ground Source heat pumps are generally more expensive to install than their air-source counterparts. One of the reasons they cost more is because they can be more difficult to install.
However, although ground source heat pumps may cost more upfront they can be cheaper to run in the long run due to being able to take advantage of the ground temperature which can be pretty constant.
There are two parts to installing a ground source heat pump – the internal install of the ground source heat pump itself. This install will look similar to a boiler, you will have a box installed within your property. You will then also need to install the ground array outside the property.
The way you install a ground source heat pump will depend on the type of ground array collector you use.
Slinkies or straight pipes
To install a ground source heat pump with slinkies or straight pipes you generally need a fair amount of land around your property.
Trenches will be dug outside of your property and the pipework will be layed in these trenches. This type of collector can require a fair amount of garden space, however is often the cheapest ground array option. The larger the home you need to heat, the bigger the ground loop will need to be.
Boreholes
To install a ground source heat pump with boreholes you need much less space than you would for slinkies or straight pipes.
Boreholes only need a small amount of space on your property, generally only 155mm of space per borehole of which you will likely only need one. You will need to drill deep into the ground to install the underground pipework that contucts heat from rock under the surface.
Pond mats
If you are planning to use water to provide heat to your ground source heat pump you will need to use pond mats to tansfer the energy.
Any large body of water near your home can be used for this like a pond, lake, river or aquifers. Ground source heat pumps that use water as a heat source can also be known as water source heat pumps.
Here are the different types of heat pump.
Who can install a ground source heat pump?
The external work to install a ground source heat pump will generally need to be done by specialist subcontractors, however the inside installation of a ground source heat pump can be done by a good heating engineer.
Ground source heat pumps should be MCS approved, this means that they need to be installed by either an installer who is MCS accredited, or an installer who is working under an MCS umbrella.
What types of properties can you install a ground source heat pump in?
Ground source heat pumps are suitable for a wide variety of properties. Due to the different ground arrays they can be installed in most properties with enough outdoor space for the drilling or digging equipment to operate in.
Ground source heat pumps are suitable for both new build and retrofitting in properties. With shared ground arrays, they can even be used in high rise tower blocks, densly populated terraced homes as well as detached houses with large gardens where a private ground array may be possible.
The ground array type used and the means of deploying the ground source heat pump will differ depending on property type.
If you are looking to privately install a ground soure heat pump into your property it is likely that you will need some outside space so detached or semi detached properties would work well.
Here is how much space a ground source heat pump needs.
How does a Ground Source Heat Pump Work?
Ground source heat pumps use a network of underground pipes (known as a ground loop) and a heat pump above ground. They pump anti-freeze and water around the ground loop and naturally absorb heat from the ground.
Before giving off heat to your home, the water and anti-freeze mix is compressed and goes through a heat exchanger which will take the heat and transfer it to a heat pump.
You can use a ground source heat pump to power your central heating, heat water for washing and cleaning and even to provide underfloor heating.
Advantages of a ground source heat pump
- They can be very efficient due to using less power than the heat that it creates
- They can have lower running costs and cut your energy bills
- You may get financial support from the government to install one
- They can also offer cooling
- They are easy to maintain
- They are very quiet and cause very little disruption
- They can be small enough to fit inside a kitchen cupboard (depending on the make and model)
- They can be cheaper to run than an air source heat pump due to fewer moving parts than an air source heat pump.
- Ground source heat pumps can also be more efficient than air source heat pumps because ground temperatures remain at a constant 10-12 degrees whereas the air temperature will vary more dramatically, meaning an air source heat pump will have to work much harder in cooler temperatures to provide heat.
Disadvantages of a ground source heat pump
- Ground source heat pump systems are expensive to install (can cost between £10,000 – £18,000 according to EST)
- You may have to dig up your garden
- You need to have the space to have the heat pump outside
- Better for homes with large radiators or underfloor heating systems
- Electricity is still needed to power the pump
How much do ground source heat pumps cost?
Heat pump costs vary, Ground Source heat pumps are much more expensive and can range between £10,000 to £18,000. You may also need to consider the costs of extra insulation and any new radiator or underfloor heating system, which could add value to your home. You will need to factor in the cost of labour too.
There is government funding available under the boiler upgrade scheme, this is currently valued at around £6,000.
Domestic ground source heat pump installations are also eligible for the 0% VAT.
How long do ground source heat pumps last?
Ground source heat pumps can last about 25 years, over 10 years more than a traditional gas boiler. The ground array infastructure is generally expected to last around 100 years.
Are ground source heat pumps worth it?
Ground source heat pumps are a great low carbon alternative to a gas boiler. If the UK is going to reach their Net Zero ambitions, we need to be switching over to environmentaly friendly heating systems.
Although ground source heat pumps can be costly to install up front, there are new funding options and cost savings being developed all the time to make them more accessible to the masses.
You may pay more for a ground source heat pump upfront, however, you are likely to make savings in the long run due to lower maintance and running costs.
Ground source heat pumps can provide efficiencies of up to 400% in comparison to gas boilers which are just over 90% efficiency. This means that for every unit of enery used ground source heat pumps provide up to 4 units of heat, whereas a gas boiler would offer less than 1 unit of heat for every unit of energy, this makes them a much more energy efficient technology.
If you are planning on staying in your property long term and have the capital available, a ground source heat pump is likely to be the best value low carbon heating system in the long term.
However, if upfront cost is an issue, there may be other low carbon heating solutions that suit your needs better.
Can ground source heat pumps provide cooling?
Ground source heat pumps can provide cooling. They can either do this passively without the heat pump needing to be turned on, or the heat pump can be run in reverse for active cooling similar to an air conditioner.
Passive cooling is likely to bring the temperature of the room down to a manageable temperature rather than cool it completely like air conditioning. However, active cooling from a ground source heat pump works like air conditioning. It takes heat from the room and runs the heat pump backwards to put the heat back in the ground and cool air into the room.