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14 May 2021

Installing a ground source heat pump

We talk you through how ground source heat pumps are installed and, more importantly, whether your home is suitable for one.
Engineer client 465228
Which? Team

Ground source heat pumps aren't recommended for all homes. If your home isn't suitable, you could end up with a system that doesn't deliver for you or your money. Our guide can help.

Below, we explain all the things you need to consider before taking the plunge with a ground source heat pump, from the difference between a horizontal and vertical pump system, to how to find an approved installer.

Should I buy a ground source heat pump?

When it comes to taking the plunge with a ground source heat pump, there are a couple of checks to tick off. 

Here are five key things you need to think about if you are considering installing a ground source heat pump:

1. The size of your home

You'll need to have enough outdoor space to support the ground loop and pump, and access for digging machinery. Get an installer to advise on your particular circumstances.

2. Existing fuel system

Savings will be greater if you replace an old or expensive heating system (such as LPG or electric heating), than if you're connected to mains gas.

3. What heating system you're using

A ground source heat pump produces low-temperature heat, so is best connected to a low heat system - such as underfloor heating.

Radiators are unlikely to achieve the same heat you might be accustomed to from boiler-powered central heating. 

4. Water heating

You may need a separate electric immersion heater.

5. Insulation

Before considering a ground source heat pump, improve your home's energy efficiency with loft and cavity wall insulation.

If you don't take the appropriate steps, you'll be paying to generate heat you're making little use of.

Find out how much money you could save by installing loft and cavity wall insulation

Horizontal and vertical systems: what's the difference?

The ground loop (the network of pipes pumping the water underground) can be fitted horizontally or vertically. The type of system you choose depends on the space you have available. 

Horizontal systems are laid in a shallow trench over a wider surface 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 hand, a vertical system buries the pipes in a borehole. Depending on the size of the system, the borehole could be anywhere between 15 and 100 metres deep. 

Whatever type of ground source heat pump you install, it's important that the system is correctly sized for your heating needs.

How to install a ground source heat pump

If you're considering installing a ground source heat pump, make sure you use a Microgeneration Certification Scheme (MCS) installer and get a properly accredited professional to complete the work. 

The Energy Saving Trust (EST) conducted a ground source heat pump trial between 2008 and 2013 to find out more about how people are using heat pumps and how efficient they are. During the course of the trial, the EST found a variety of pumps that were incorrectly installed. This meant they didn't perform as efficiently overall. 

It's essential to use an MCS-approved product and installer to qualify for the Renewable Heat Incentive (RHI), which is a government scheme paying householders who have renewable heat technologies. Find out more in our guide to the Renewable Heat Incentive.

There are rules on how heat pumps can now qualify for MCS, which makes it even more important to make sure the heat pump you're thinking of getting is MCS-approved. You can check this on the MCS website (search for 'product search').

We always recommend getting several quotes before choosing the best option for you. The installation of a ground source heat pump typically takes one to two days for a professional installer to complete. 

Heat pump energy labels

New regulation means that heat pumps have to have an energy label on them. The label gives information about the energy efficiency of the heat pump and rates products from dark green (most efficient) to red (least efficient).

From 26 September 2015, all new heat pumps that entered the market had to be sold with an EU product label, and the installer had to produce a package label that displays the efficiency based on several different components in the heating system.

Since 25 March 2016, all heat pumps certified by the MSC have to be sold with a product label, and the installer must produce a package label. If your heat pump is not sold with a product label, it may not be eligible for the RHI.

Heating controls

Ask the installer how you'll be able to control the ground source heat pump system, as understanding how to operate it efficiently will help you to get the most out of it. 

Make sure the controls are user-friendly and the installer explains to you how to work the system. The Energy Saving Trust's field trials found that many control systems were too complicated for homeowners to work effectively.

Your heating controls should allow you to pre-program your system to switch on or off at different times.

For more tips on how to get the most out of a ground source heat pump, see the results of the ground source heat pump user trial.


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