Heat Pumps In The UK | The What, The How & The Why

How does a heat pump work? What’s the best type and brand for the British climate? This buying guide will help you understand the important features and the potiental disadvantages .

Renewable energy sources are becoming more and more popular and, heat pumps are gaining popularity as an ecologically friendly substitute for fossil fuel burning heating systems. Getting heat pumps installed in your home is beneficial as it produces clean energy and helps you reduce your utility payments at the same time.

What’s In This Guide?

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The basic working principle of a heat pump is to move heat from one place to another while using a limited amount of energy. In conjunction with a heat pump, you can use renewable energy sources such as solar and minimise your carbon footprint further. The principal sources of thermal energy that a pump uses, are air and ground(geothermal) and these heat sources lend their names to the two main system types.

How A Heat Pump Works

As mentioned previously, a heat pump extracts heat from one source outside your home and moves it your living environment. These systems work in the same way the traditional refrigerator and the air-con systems popular in warmer climes do.

The device works by circulating a liquid refrigerant through a continuous process of condensation and evaporation. The refrigerant is pumped in between heat exchanger coils. At the first coil, the refrigerant hits low pressure causing it to evaporate and it takes in the latent heat in it’s surrounding environment. It’s then compressed at the second coil where the it condenses releasing the previously absorbed heat. And the cycle starts again.

The various heat pumps work in this way with minor differences due to the medium they are extracting heat from.

The great thing about this system, is that the process is fully reversible in that in the summer months the system can cool your home whilst in the winter, it can keep you nice and snug.

Heat Pumps Types

You can choose from different types of heat pumps which will depend on your energy needs and the characteristics of your house. So, they come in two main types: geothermal and air source.


Geothermal (aka ground source) heat pumps include a diversity of heat pump systems. Geothermal heat pumps include pond heat pumps, horizontal and vertical systems, closed or open loop systems and more. Here is a list of geothermal heat pumps types:

Closed-Loop Systems

One of the most popular types of heat pumps is a closed-loop ground source. It works on the principle of circulating antifreeze liquid through closed plastic tubes that are buried underground. Vertical and horizontal ground source heat pumps are the most common systems.

Vertical Ground Source

This type of heat pump system is great for areas or properties with limited space. The system is installed with holes drilled vertically into the ground. The boreholes should have a distance of about five meters between each other and each borehole can be  drilled to a distance of between 15 and 122 meters deep.

The ground temperature below 15 meters is not influenced by seasonal changes so you and your family can enjoy stable temperatures.

Horizontal Ground Source

The horizontal ground source heat pump system is significantly cheaper than the vertical one but requires a lot more space. No boreholes have to by drilled, but trenches below the frost line for coiled pipes must be dug. In these trenches, the coiled pipes for refrigerant are placed. One disadvantage of this system is that the seasonal weather changes can influence it.

Radial or Directional Drilling

Radial drilling is becoming more and more popular in recent years. It’s more expensive but has several benefits. 

First a ‘drilling chamber’ is dug into the property. This chamber allows a specialised piece of equipment to bore holes in a radial fashion in all directions. Using this system, customers benefit from a much better coefficient of performance (COP) and will gain more heat from the property. It also means that trenches don’t have to be dug.

Direct Heat Exchange System

The basis of this system involves the refrigerant moving underground in the copper tubes. The underground surrounding geology heats them up, and then the heated refrigerant returns to the house.

Open-Loop Systems

Open-loop systems, or ground water source heat systems, pump water of a certain temperature from below the ground. After extracting the temperature out of it, the water returns to the ground through another pipe.


Air Source Heat Pumps

There are two main kinds of air source heat pumps: air to water heat pumps and air to air heat pumps. Both types operate by the basic vapour compression cycle mentioned above.

It may surprise you but there’s a usable amount of heat outside even on cold days. Air source pumps can extract usable heat from the atmosphere even at sub-zero temperatures. But there are some considerations.

Considerations When Installing Heat Pumps


Heat pumps are rather durable and can last up to 20 years or longer, but, like any other system, they require a regular check-up and maintenance. Some particular parts of the system you can check yourself, and you should probably do this once a year.

However, every three to five years, you should hire a professional installer to inspect the system carefully. After a professional examination, you will receive a detailed description of the system’s condition and additional information concerning any potential issues that may occur in the future. Unless any essential safety examination is needed, the maintenance requirements won’t be too high. Before you restart your system, you will usually need to check the pump, outside tubes, and electronic parts.


Usually, the warranties for heat pumps last for two to three years, however, there are multiple sub insurance options available. The warranty for the installation services can last up to ten years. Additionally, it can depend on the company that you choose to work with. Some companies in the UK offer a warranty for their heat pump systems for up to five years.


When you are planning to install a heat pump system in your home, you should also be aware that there are grants available that will provide you with the reduction. One such option is offered by the SEAI under the Better Energy Homes Programme – it is a heat pump system grant.

In order to qualify for the heat pump system grant, you have to meet certain requirements. Firstly, your dwelling has to have a low heat loss. It is essential to ensure uninterrupted performance of the heat pump system and that your energy bills are not getting higher. It is recommended to consult with an SEAI registered consultant before applying for the grant. They will be able to assess your home and inform you what you should do to reduce the energy loss in your house and make it ready for the heat pump installation.

With the heat pump system grant, you can avail of multiple benefits. If your home is well insulated, you can improve your energy efficiency and reduce your energy bills at the same time. Your heating system will be eco-friendly, and you will reduce your carbon footprint by reducing your reliance on fossil fuels.

You can apply for this grant if you are a homeowner or a landlord of a house that was built and occupied before 2011.

If you are interested in the installation of a heat pump system on your property, you will need to find a reliable company that has qualified specialists who can perform the work to the highest level.