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Questions to Ask Before Getting a Ground Source Heat Pump Installation

You might be familiar with the term ground source heat pump but not exactly be too sure if it's right for your home or perhaps just wish to learn a little more about them. With that in mind, we explain a few of the things you’ll want to ask before taking the plunge with a ground source heat pump. Read on to discover more!

What is it?

Ground source heat pumps take in energy from the sun warming the ground. They also comprise a series of pipes which are based underground which absorb solar energy. This energy is then converted into heat for usage in the home.

There are two key elements of a ground source heat pump system:

  • The ground array, which is located underground. 

  • This can be vertical or horizontal. 

The heat pump itself is installed in the house. Some of these include a hot water cylinder and can be the size of a big filing cabinet. The smaller pumps can be installed in an under-sink kitchen cupboard. 

How Do Ground Source Heat Pumps Work?

A combination of water and antifreeze is pumped around the ground array. This takes in the solar energy stored in the ground. Heat is extracted using compression and expansion technology, making the energy able to heat the house.

The amount of heat available to be collected will be influenced by:

  • Capacity (the amount of piping and the length of the trenches required)

  • The soil conditions - for example, clay withholds more heat than sand does

  • A good installer will look at the ground conditions before designing and sizing a ground source heat pump system

How will a Ground Source Heat Pump be Installed?

It varies on whether you have a horizontal or a vertical array, and this will be contingent on the space available and the ground conditions. 

A horizontal array consists of a piping laid in a serpentine closed loop in a trench, often 1.2m deep. You will require a fairly big garden or outdoor space, permit 500m² for a 10kW heat pump in clay soil, and twice that for sandy soil. Pipes could be a straight pipe or in coils, known as a ‘slinky’ pipe.

Should I Buy a Ground Source Heat Pump?  

When it comes to taking the plunge with a ground source heat pump, there are a few things to check. Here are a few of the main things you need to consider about if you are thinking of installing a ground source heat pump:

The size of your property

You'll need to have enough outdoor space to support the ground loop and pump, and access for digging machinery. It's recommended that you get an installer to advise you on your specific circumstances. 

An existing fuel system

Savings will be more significant if you swap an old or expensive heating system (such as LPG or electric heating) than if you're paired to mains gas. 

What heating system you already have in place 

A ground source heat pump produces low-temperature heating, its best-connected with a low heat system - such as underfloor heat. Radiators don't often achieve the same level of heat you may be used to from boiler-powered central heat. 

Water heating

You could require a separate electric immersion heater.


Prior to considering a ground source heat pump, it could be worth checking the quality of your home's energy efficiency with loft and cavity wall insulation. If you don't take any necessary maintenance measures otherwise you'll be paying to generate the heat you're making little use of.

Horizontal and Vertical Systems: What's the Difference?  

The ground loop (the network of pipes pumping the water underground) and as previously mentioned, it can be fitted horizontally or vertically. The type of system you opt depends on the space you have available to you. Horizontal systems are laid in a shallow wider area. The Ground Source Heat Pump Association estimates that a new-build three-bedroom house (around 120m²) would need two trenches which are 30 to 40 metres long. On the other end of the spectrum, a vertical system buries the pipes in a borehole.

Do you have access to the ground?

This could seem obvious, however, you'll have to check that you have a big enough patch of land. Most systems in the UK utilise heat collecting pipes (loops) buried in shallow trenches and you have to check that you have enough area to install these, particularly if you need to warm a standard-sized building. Other than this, it's possible to place the heat collector in a vertical borehole, which only needs a limited surface area for access.

Is your property well-insulated?

As with a new heating system, it's important to consider a ‘fabric first’ approach and ensure that the heat you produce is not wasted due to poorly insulated walls, ceilings and floors. When organising a new heating system, it may be more cost-effective to add extra insulation, this is so to decrease the capital cost on installation and the running costs of using it. 

How big a system do you need?

Once the heat loss through the fabric of your home is understood, you can calculate the heat demand under typical winter weather conditions that would be needed. This calculation will also consider whether domestic hot water (DHW) is to be necessary either wholly or partially from the heat pump itself. This can then be transferred to offer optimal size for the heat collector loops (whether in trenches or a borehole). The installer can also advise whether the ground conditions will allow summer heat replenishment around the collector loops that will enable good heat extraction in cooler months for years to come.

Can you combine my heat pump with other methods of heating?

Ground source heat pumps often work best when raising water to a temperature around 40°C, and so are well matched to a wet underfloor heating system, despite being 'oversized' radiators can be used as an alternative. As it's not often cheap to fit a wet underfloor heating system into an existing property, ground source heat pumps are most commonly installed into newer properties. They can be put in place in older buildings if attention is given to allowing better insulation and - if it’s necessary - increasing the size of the heat emitters such as radiators​.

How efficiently do heat pumps perform over time?

The source of the heat is accumulated by the ground loops is the sun's energy that heats up the surface of the earth and gets absorbed by the ground. The only standard energy used in a ground source heat pump system is electricity for the pumps and compressors, which is needed to run the system. Often, these utilise only a quarter as much energy as is released into the building in the form of heat so a ground source heat pump can be 300-400% efficient.

The overall quality of a ground source heat pump depends greatly on the quality of the design and installation. Maximum performance is reached by matching the specification of the installation to the needs of the building and its use and ensure that a balance of heat exchange is maintained within the ground over the year in a sustainable way by utilising solar recharge of the ground.

We Offer Ground Source Heat Pump Installation 

One of the most reliable and energy-efficient ways to control the temperature within your premises is to install an air source heat pump. Whether you live in a colder or warmer climate, top of the range ASHP heating systems can convert cool air into heat energy to warm up your building and make the environment perfect for you, your family or your employees. In fact, heat pump systems can be up to four times more efficient than traditional alternatives, such as radiators or boilers. 

If you’re seeking a heat pump installation, then you needn’t look further than Westcott Air Conditioning. We supply only the highest-quality ASHP heating equipment from the popular Mitsubishi range, chosen by our heat pump installers because of its energy efficiency and quiet operation. To find out more about the services we offer, please get in touch with us today, we’d be happy to help! 

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