Ground source heat pumps: Everything you need to know

Consumers have a lot to consider when heating their homes. The rising cost of energy is a huge factor that affects everyone. Choosing a sustainable energy solution for the home is a priority for many as well.

Finding a way to harness natural energy sources can be the perfect solution. However, selecting the right natural energy source for your home isn't always easy.

Ground source heat pumps are one option that is growing in popularity. Government incentives to reduce carbon emissions have encouraged homeowners to invest in greener energy options, like these heat pumps.

This article has all you need to know about ground source heat pumps, so you can make an informed decision about heating your home.

What is a ground source heat pump?

A ground source heat pump is a heating system that draws heat from the ground and transfers it to your home.

Radiation from the sun hits the Earth's surface and is stored beneath the ground.

The renewable energy heating system uses a network of pipes filled with water (or a combination of water and antifreeze) to take solar energy trapped underground or in ground water and circulate it into a building.

Horizontal or vertical ground loops are used to cover a larger area, depending on where they're installed.

• Vertical ground source heat pumps require less land as they are buried vertically. However, the installation process needs specialist equipment, just as a drill is needed for a borehole.
• Horizontal systems require a significantly larger area of land, but the trenches required are easier to dig than drilling for vertical systems.

Vertical systems are more efficient geothermal heating solutions, because they are installed further underground and can access greater temperatures.

Water source heat pumps are another option, but are less common than horizontal or vertical ground source heat pumps.

How does a ground source heat pump work?

A network of looped pipes is installed around the property.

A mixture of water and antifreeze is pumped around the system, absorbing the geothermal heat. Electricity is used to compress the mixture, which is then passed through a heat exchanger.

This heat exchanger heats up water, just like normal gas boiler systems. This hot water can then be stored in a hot water cylinder for domestic use or pumped around the home's central heating system to heat underfloor heating systems or radiators.

How much do ground source heat pumps cost?

The cost of a ground source heat pump will vary depending on the size and type of system. The size of an efficient heating system is dependent on the size of the property. The bulk of the cost for ground source heat pumps is in the installation. Significant groundwork needs to be carried out for both options.

A vertical ground source heat pump will require a large area of land to be cleared and trenches dug for the installation. Vertical systems don't require as much land, but they do need specialist drilling equipment for installation.

The total cost of a horizontal ground source heat pump system for an average two-bedroom property may be up to £20,000. Vertical systems would typically be slightly higher at around £22,000.

Systems for three to four-bedroom homes see costs rise to over £25,000 for horizontal systems and closer to £50,000 for vertical systems. Vertical systems for larger properties need to be drilled down further, making the installation significantly more expensive.

The UK Government's Boiler Upgrade Scheme which was launched in the spring of 2022 and is due to end in 2025 can help reduce costs. The Boiler Upgrade Scheme offers grants up to £7,500 towards installing ground source heat pump systems.

Other factors will impact the system requirements for your property. One of the most significant of these is the level of insulation your home has.

Properties with cavity and loft insulation, as well as energy-efficient windows, are better suited to this type of heating system. Older properties that aren't as energy efficient might struggle.

What are the benefits of ground source heat pumps?

The best way to decide whether a heating system suits your needs is by weighing up the advantages against the disadvantages. The following information will help you come to an informed decision about whether a ground source heat pump is right for your home.

1. Cheap energy

One of the biggest reasons that people are exploring ground source heat pumps as a heating option is because of rising energy bills.

If you are on a fixed tariff, you may be anxious about it ending and having to renegotiate. If you are already on a variable rate, your heating bill might be growing each month.

The Energy Saving Trust estimates that properties with old-style electric storage heaters could save as much as £1,600 per year.

Having access to a renewable heat energy source that can reduce bills is a great incentive. Despite high installation costs, the low running costs still make it a tempting proposition.

2. Green energy

Another huge incentive is that it can reduce carbon emissions. Ground source heat pumps can be a great alternative to gas boilers.

They use a ground loop to absorb heat efficiently before transferring it to your home, so you can take advantage of the ground heat and thermal energy lying beneath your property.

The Energy Saving Trust estimates a ground source heat pump can save as much as 7,000 CO2 kg/year when converting from coal systems.

3. Low maintenance

Another benefit of installing a ground source heat pump is it requires very little maintenance. The pumps themselves will typically last a similar period as a regular boiler.

The ground loop system can last as long as 70 years, so you don't need to worry about replacing them for a long time.

4. Consistent heat supply

You might think that the ground temperature will be affected during the winter. While the top layer may be frozen or frosty, there is still sufficient natural heat further down where your ground loop system will be buried.

This can also be beneficial to homeowners if there are issues with a gas supply or maintenance work that cuts your supply for a period of time.

5. Great energy efficiency

A ground source heat pump improves your home's energy efficiency in several ways. The first being that it reduces the amount of gas you need for heating. By making use of a renewable energy source on your property, you will benefit straight away.

Another reason ground source heat pumps can improve efficiency is how they heat the home. This type of system does not run as hot as a gas boiler system. This will encourage the homeowners to implement measures in the home to improve efficiency, such as improving the home's insulation.

What are the disadvantages of ground source heat pumps?

While there are significant advantages, there are also disadvantages. These include:

1. Installation costs

There is no getting around it: the installation costs of ground source heat pump heating systems are off-putting. Whilst the long-term running costs may be low, the initial outlay for installation is tens of thousands of pounds.

Government grants are in place to help reduce this cost, but they can still be expensive.

2. Suitability of a property

Not all properties will have suitable areas to install ground loops.

Gardens need to be large enough - horizontal heating systems usually require several hundred square metres.

The area would need to be clear of trees or outbuildings. Tree root systems can cause issues with ground loops so this is essential.

3. Might not suit current heating systems

Modern heating systems and boilers are designed for efficiency and aesthetics. This can mean smaller, more powerful radiator systems.

A ground source heat pump does not generate the same heat as conventional heating systems. This means the water that flows around the central heating system will not be as warm. Using radiators that conduct heat well is important. In this case, aluminium is a perfect material.

Ground source heat pump systems are good for people that plan on fitting underfloor heating. The type of heat generated is better suited to constant heating rather than short bursts of heat provided by direct electric heating systems.

4. May require home improvements

Preparing your home for a ground source heat pump can also be expensive. As well as considering the installation costs of the system, you will have to consider whether your home is suitable.

The heating systems in your home should be able to emit the heat required to provide your home with an ambient temperature. Installing underfloor heating can be a great idea for newbuilds or remodelling.

The home must also be well insulated for this type of heating system to be effective. Preparing a home for a ground source heat pump will be beneficial, but it can be expensive.

How efficient are ground source heat pumps?

A ground source heat pump will still need to use electricity. However, its Coefficient of Performance (COP) shows it is one of the most efficient heating systems available.

The COP is a ratio that determines the power required by a system in comparison to its output. The COP of an average ground source heat pump is around 4. This means that for every 1 kW (unit) of energy required to power a heat pump, it generates 4 kW (units) of heat.

Is a ground source heat pump right for my home?

Determining whether a ground source heat pump is right for your home is essential before making your decision. You need to ensure your property is suitable, and that you will be able to generate enough heat for your hot water and central heating needs.

• A well-insulated home is a must for this type of heating system. Being able to keep an ambient temperature in your home without too much effort is best.
• The best heating systems for the home include larger radiators and underfloor heating.
• You must also ensure you have the space on your property if you plan to install a horizontal system in your garden.
• The pump is also relatively large and installation in basements or outbuildings is best. The system works best when there is less space or temperature difference between the ground loops and the heat distribution system.

A good installer will be able to advise on the size and positioning of the equipment required.

Final thoughts

There has been lots of publicity about renewable heating solutions over the last few years. Rising energy costs have also helped to improve the public's knowledge of these systems.

A heat pump could be a great option to reduce your carbon footprint. However, there is still some way to go before it matches the performance of traditional boilers.

Our energy-efficient boilers are all installed by Gas Safe registered engineers. They can provide hot water and warm radiators almost immediately.