Although the humble boiler dominates most homes' heating systems, ground source heat pumps are a greener — and potentially cheaper — alternative that may suit your needs.
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Very few homes in the UK have anything other than a boiler heating the home and, while this fairly old technology has become increasingly efficient, the rising cost of gas means many households are looking for cheaper and greener solutions.
Potentially more environmentally friendly, ground source heat pumps are a cost-efficient solution to boilers. In this guide, we help answer whether a ground source heat pump is right for your property, if it can save you money, and what the pros and cons are.
What is a ground source heat pump?
Ground source heat pumps are basically like circular wells, pumping water down into the ground and back out again to heat your home. The ground source heating units, which are placed on the outside of your property, use the natural heat found in the ground to increase the temperature of the water pumped through it.
Inside the ground source heat pump, you will find an evaporator, compressor and condenser. After the water is pumped back out of the ground, they then further increase the temperature of the water using the compressor unit, and this heated water then flows into your home's heating system.
Are ground source heat pumps a renewable energy source?
Generally speaking, yes. Ground source heating uses less CO2 than other forms of heating systems, particularly electric heating or coal. It isn't, however, CO2 free, as the compressor unit still requires electricity to run.
Because the heat pumps are generating their energy from a renewable source — that is, the earth itself — ground source heating is considered a renewable form of energy. This means that having a ground source heat pump generating your home's heating may entitle you for payment under the Renewable Heat Incentive scheme.
According the the Energy Saving Trust in 2019 the incentive for using ground source heat pumps is between £2,380-£2,585.
Ground source heat pumps are also more energy efficient than their close relatives, the air source heat pump, but are more difficult to install.
Is a ground source heat pump suitable for my property?
A ground source heat pump is a fairly big piece of equipment, much of it underground, and therefore requires some extensive work to have it installed. The main issue is determining whether your garden is suitable for the ground loop system to be installed.
The ground loop is typically placed in trenches roughly two metres in depth, but in smaller gardens the loop can also be dug vertically to a depth of 100m.
Therefore, the garden has to be suitable for digging and have easy access for sizable digging machinery. The good news is that once the system is installed, it needs very little maintenance, and isn't reliant on a steady external heating fuel supply or deliveries — such as the case with some different types of boilers.
It is also worth noting that ground source heat pumps will generally heat your unit at a slightly lower temperature than traditional gas or electric units.
This lower temperature also means that ground source heating systems are typically left on for longer, particularly in the winter months.
Finally, the type of heating system the unit is feeding, and the fuel it is replacing, will determine whether a ground source system will save you money.
The unit will also save you much more money if it is replacing an electric or coal-based system. If your home is on mains gas it may not be a suitable option.
How much does a ground source heat pump cost?
Ground source heat pumps are not cheap to install, although costs will vary. The typical price range for a full installation is between £10,000 and £18,000, but running costs will depend on your property, its size, and how well insulated it is.
Either way, it is a serious investment, but there are a number of reasons why it could be worth it.
Running costs are likely to be lower than previous systems, with the difference dependent on what you are switching from. Switching from gas heating system will give you the lowest savings figures, whilst a typical home switching from electricity heating could save over £500 a year.
It is crucial your system is set up correctly. With key differences in terms of the level of heat produced and how long it should be left on for, you will need the installer to talk you through the optimum settings. Finally, ground source heat pumps are very low maintenance, so you shouldn't have to worry about paying an engineer to fix it all the time.
What are the advantages and disadvantages?
The main advantages of a ground source heat pump are:
- They are environmentally friendly compared to other heating systems
- You may be eligible for payments under the Renewable Heat Incentive scheme
- Ground source heat pumps are low maintenance once installed
- They use a renewable resource efficiently
The main disadvantages of a ground source heat pump are:
- They are expensive to install
- They are most effective if you have underfloor or air heating systems
- The installation process will mean significant work and disruption to your garden
While ground source heat pumps clearly aren't suitable for every house and require a lot of work to install they can be worth the effort and could help reduce your energy bills.
If you're looking to cut your bills remember to do the basics right as well, from properly insulating your home and installing draught-proofing to closing doors to unused rooms. For more advice you can read our guide to energy-saving tips and start making small changes to save a lot of money.