How Do Ground Source Heat Pumps Work? (Explained)

How do Ground Source Heat Pumps Work

As energy costs rise and people search for ways to lower their carbon footprint, all renewable energy options are worth exploring. With ground source heat pumps, we also get air source heat pumps, hydrogen ready boilers, and other natural gas alternatives.

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One option that proves popular among some homeowners is ground source heat pumps.

This article will take you through everything you need to know about what a ground source heat pump does, how it works, the types of heat pumps available, how they are installed, the benefits, and the cost of a ground source heat pump.

Gathering all the information you can about heating systems for your home will help you to make an informed decision about the best system to suit your needs and whether they are a viable option.

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What does a ground source heat pump do?

As the sun’s radiation hits the earth, the energy in the form of heat is stored beneath the surface of the earth. By digging down roughly two metres, you can get access to this heat of around 10°C, even during the winter months.

The ground source heat pump harnesses the underground heat, which is then transferred to the home. This is not to be confused with an air source heat pump which uses heat in the air to warm up your home.

How does a ground source heat pump work?

A ground source heat pump uses a network of looped water pipes that are buried beneath the ground at a level where they can harness the earth’s stored heat, this is the opposite to air source heat pumps that draw warmth from the air.

A combination of anti-freeze and water is then pumped through the pipes, absorbing the ground heat before being passed through a heat exchanger.

The system then uses electricity to compress the water and anti-freeze mixture.

The heat from the compressed water and anti-freeze mixture that passes through the heat exchanger is then extracted and transferred to the heat pump, which is then used to move the heat around your home.

The heat can be passed around your home heating system by a network of pipes to radiators or underfloor heating. It can also be stored in hot water cylinders that are then utilised for hot tap water, baths, and showers.

What do you need to get a ground source heat pump installed?

Because the ground source heat pump will be buried, you will need a home with a garden that can be accessed by digging equipment.

The pump machinery will be housed above ground, so you will also need space for this to be located in a suitable position near the home so the system can efficiently pass heat.

The equipment needed for a ground source heat pump includes the ground loop that is buried and collects the heat and the heat pump that increases the temperature and transfers it to the home.

There’s also your heat distribution system that is usually made up of a network of pipes, and the hot water cylinder to store the hot water generated.

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Home uses for ground source heat pumps

Compare to a gas boiler, there are some serious things you may need to do to your home just to be able to use a heat pump effectively and save money on your energy bills.

These are very expensive also, but a ground source heat pump can provide a number of heating solutions for your home depending on your needs, and these include:

Underfloor heating system

An underfloor heating system can be a great way to ensure your home is heated sufficiently using ground source heat pumps.

The heat generated by this kind of system is more suited to heating solutions like this, as is the case with an air source heat pump too.

Underfloor heating uses a lower temperature over a more extended period of time to heat the room efficiently. Where some radiators will heat up more quickly, the heat is only generated in one area of the room and relies on airflow to spread the warmth. Underfloor heating efficiently and evenly heats the entire room.

Radiators

If you are using a ground source heat pump to heat the radiators in your home, you will be better served by large radiators. Like underfloor heating, large radiators heat the room at a lower temperature over a more extended period of time.

Renewable heating sources are much better for this type of heating solution compared with traditional boilers that can generate high temperatures. The heat pump system is a more environmentally friendly way to heat your home than a traditional gas boiler.

Hot water

Using a hot water cylinder to store the hot water generated by the ground source heat pump system, you will be able to provide enough hot water for your home, similar to the way conventional heating systems would.

Types of ground source heat pumps

Deciding on the type of ground source heat pump to suit your home is most likely to hinge on the heat pump installation and the available garden space that you have to work with. There are two variations of ground source heat pump systems that you will be able to consider for your home.

Horizontal ground loops

Horizontal ground source heat pump systems require long trenches where the pump loops are then laid. The work will be carried out across a wider surface area, and it is estimated that a three-bedroom, new build house with a floor space of roughly 120m² will require two 30-40 metre long trenches in the garden to generate the energy needed to heat the home.

This can pose many problems as not everyone has the space available to do this, and those that do may have trees or other garden features that they don’t want to be disrupted or removed. There is another option for this kind of situation, vertical ground loops.

Vertical ground loops

Where horizontal ground source heat pump systems require a lot of outdoor space to lay the loops, vertical ground loops can use considerably less space by drilling a borehole straight down. The depth of the hole made will depend on how large a system is needed to generate the energy to heat your home.

While horizontal systems have space and obstacle considerations, vertical systems will have to take into account underground pipes, sewer systems or other underground obstacles.

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Benefits of a ground source heat pump

Anyone considering a new heating system for an older house or the system they want to be installed in their new build will have a lot to think about. Being able to weigh up the pros and cons of each will help you to decide on the best system for your home.

Ground source heating can offer a number of benefits to the homeowner, including, and with the gas boiler ban in 2025 looming, you may need an alternative. If you want a boiler that isn’t covered by the ban, check out a green boiler.

Save on energy bills

Using renewable energy sources to heat your home can help you make great savings on your energy bills.

Reduce your carbon emissions

The solar energy stored in the ground provides homeowners with a clean energy source for heating homes and water. It is worth noting that they will still require electricity, so you won’t completely erase your carbon footprint with this heating solution.

Despite using electricity, it can be as much as 75% more efficient than other heating systems because of the energy produced compared to the electricity used.

Access to RHI and other schemes

Anyone considering renewable heat sources, like ground source heat pumps or air source heat pumps, should take the time to explore the renewable heat incentive scheme.

Signing up for the renewable heat incentive scheme (RHI) can help you with grants to reduce the cost of installation, as well as to offer homeowners payments based on the energy they produce.

This will help to reduce initial costs and also reduce ongoing bills, making renewable heat sources a more attractive and accessible option for people that might have been concerned about costs.

Can help with heating and cooling

Another great benefit offered by some heat pumps is the ability to reverse the system during the summer to help cool your home. This versatility can help with the decision, and when you consider the costs of separate heating and cooling systems, it can also be seen as a sound financial decision as well as a convenient one.

Low maintenance

After installation, maintenance is relatively straightforward. An annual service by a professional will help to ensure no problems are developing with the system. This will also ensure warranties are maintained, the pump is working as it should, and the optimal refrigerant levels.

You will also be able to play your part in the maintenance of your ground source heat pumps by ensuring the above-ground system is kept free of debris like dirt or leaves. This will maximise the airflow and ensure optimal performance. You will also be able to clean or replace filters and regularly check for issues that may have developed.

Are ground source heat pumps any good?

Ground source heat pumps can be great ways to heat your home in a more environmentally friendly way and reduce your energy bills. The performance of the system will be dependent on the property it is installed in and its intended use.

With all renewable heat sources, you will find it doesn’t generate as much heat as traditional heating systems, so working smart to ensure your home optimises the heat produced will help you achieve the best results.

Exploring underfloor heating options, installing larger radiators, and considering other renewable energy sources like solar power to add a bit more heat to your home can be beneficial.

Making sure your home is insulated correctly will be crucial in getting the optimal performance from a ground source heat pump system. Heating your home with lower temperatures over a longer time is dependent on the house being able to hold the heat.

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How are ground source heat pumps installed?

The first step of installing a ground source heat pump system in your home is to invite an installation professional to plan the design that will best suit your home.

They will look at existing systems and what requirements are necessary to heat your home efficiently. This will take in the type of heat pump that will best suit the property, as well as the best energy distribution system. Your installer will also look at your home’s insulation and the geography of your property.

After assessing your home, they will be able to draw up a plan for your ground source heat pump, and you should also get an estimated cost at this time.

The loop fields will be escalated and should take between one or two days to start the work. Horizontal loop fields will be buried at a depth of around 1 to 2 meters and will need a large area of land. The size of this will depend on the size of the home and the energy required to heat it.

Vertical loop systems do not need as big an area but are more expensive because of the drilling equipment required to dig the boreholes to a necessary depth.

The depth of vertical loop system boreholes can be anywhere from 15 to 120 meters. Deeper boreholes improve the efficiency of your heat collection.

The pipes are then installed in the loop fields and buried.

If the work is taking place on an older property with an existing infrastructure, the contractor will modify or replace this to suit the new system.

The heat pump will then be installed and connected to the home system and ground loop.

After installation, your new system should run with minimal issues as there are few moving parts. Regular maintenance and servicing will help to ensure the longevity of the system.

Ground source heat pump running costs

So how much does it cost to run a ground source heat pump system? This is a question many people will want the answer to as it is one of the most important factors to consider when deciding on a heating system.

To help you make a decision, we will look at all the costs involved. First is the price of the heat pump and the parts you will need. As with any product, prices will vary depending on brand, quality and size, and costs for a new system can run anywhere from £2,000 to £15,000.

Installation cost is another huge factor due to its complexity. Prices can vary from £15,000 to £25,000 depending on local labour costs, ground conditions, and the size of the job itself.

Installation in new builds can be cheaper as contractors don’t have to work around existing infrastructures, and it can be planned into the building of the house.

Now that you know about the expense involved in buying and installing a ground source heat pump, we hope you aren’t put off. There are grants and schemes in place to help reduce this cost. Investigating the RHI and boiler upgrade scheme can help to save you money on initial costs and the running of your new system.

Running costs can be between 30% to 70% cheaper than traditional heating systems like gas boilers or electric boilers. The only power needed will be the electricity that powers the circulation pumps and compressor. Other renewable energy sources like solar power can help to reduce this cost even further.

The efficiency of this system means that it can generate three or four times units of heat for every one unit of electricity it uses. Running costs can be as low as between £540 to £700 a year, making it the best value heat source on the market.

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FAQs

How long do ground source heat pumps last?

Another great benefit of ground source heat pumps is how long they last. Whereas even the best combi boiler will last on average between 10 and 15 years, you will enjoy around 25 years from this system.

With big heat pump manufacturers like Vaillant, you can get warranties of around five years for new ground source heat pumps, giving you peace of mind as you get used to the new system. Regularly maintaining the system and ensuring it is serviced annually will also help to ensure you get a long life from it.

Will a ground source heat pump pay itself back?

Over time, a ground source heat pump will pay for itself over the course of between 8 to 10 years. This will depend on the system you choose, the efficiency of the home it is being installed in, and whether you are able to take advantage of any renewable energy schemes or grants.

Compare this to hydrogen-ready combi boilers which could save you up to a third on energy bills every year and keep your home warmer, then these may be a better option.

Which types of houses are ground source heat pumps suitable for?

Homes will be suitable for a ground source heat pump, as long as they have adequate outside space for installation. For most a new boiler will be the only option, but if you can afford a heat pump and have the space, then why not. Find out the pros and cons of both here in our heat pump v boiler post

Because of the installation costs involved, new builds can be better to incorporate the system into the building design and take advantage of contractors already working on the project. However, this does not mean it should not be considered in older homes.

To ensure your home is suitable for a ground source heat pump, you will need to make sure it is heat efficient. Insulation is a key factor when installing renewable heat sources as they tend to heat homes at a lower temperature for longer. Homes that lose a lot of heat will find that the system will take even longer to heat the home if measures are not taken.

Loft and cavity wall insulation are great for combatting heat loss in the home, as is dealing with draughts at doors and windows. Installing double or triple glazing windows will also significantly reduce heat loss from your home and improve efficiency.

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