Air source heat pumps vs. ground source heat pumps

In this guide you'll find information about:

  • How air source and ground source heat pumps work

  • How air source and ground source heat pumps are installed

  • How much each type of pump costs

  • Which one is more energy-efficient

  • Which one you should get

Although many homes get by perfectly well without needing to install an air source or ground source heat pump, some homeowners choose to install them to increase the energy efficiency of their properties. But what’s the difference between an air source pump and a ground source pump? Should you prioritise getting one over the other?

In this guide, we’ll discuss the advantages and disadvantages of the two pump types, including their costs, efficiency levels and requirements property owners have to meet for installation.

How do air source and ground source heat pumps work?

Air source heat pump illustration
Ground source heat pump illustration

As you can see from the images above, there isn’t a huge amount of difference in the way the two pumps work. However, there’s a significant difference in the way they need to be installed and set up.

How are air source and ground source heat pumps installed?

Whether you get an air or ground source heat pump may depend on the installation requirements for both pump types. 

Air source heat pumps

Air source heat pumps look very similar to air conditioning units and are generally mounted onto the exterior of a property. They’re connected to internal units, though these are usually smaller than most boilers. The size of the external unit depends on the size of the property and how much heat it needs - as it will be visible to neighbours, it’s worth checking if you need planning permission before going ahead with the installation.

Ground source heat pumps

Ground source heat pumps also have internal units, but they’re less straightforward to install because they require underground pipes to be fitted. This involves digging up your garden, which might not always be possible. The pipes can be laid vertically, which means specialist equipment will need to be used, or horizontally, which is more straightforward but requires more space, so you’ll need a large garden. However, once the pipes have been laid, the garden won’t look any different than it did before, so as long as you can tolerate the time it takes the pipes to be laid, you don’t need to worry about the garden becoming unusable.

How much do air source heat pumps and ground source heat pumps cost?

Air source heat pumps generally cost less than ground source heat pumps - Boiler Guide says that air pumps should cost between £4,000 and £11,000, while ground pumps should cost between £8,000 and £12,000. This is without installation, which could mean a decent-sized increase in costs because, as previously mentioned, there’s a lot more work involved in installing a ground source heat pump than an air heat pump. 

Air source heat pumps vs. ground source heat pumps: which is more energy efficient?

Although air source heat pumps and ground source heat pumps work in pretty much the same way, as illustrated by our images above, ground source heat pumps are generally considered to be more energy-efficient than air source heat pumps. This is because the heat taken from the ground is transferred through the pipes in the garden via water, which is better at holding heat than air.

Additionally, though air source heat pumps can work at a wide range of temperatures (including as low as -15°C), they are more effective at higher temperatures, which is an area where the UK unfortunately tends to lack consistency. Ground source heat pumps, though, have much more consistent temperatures to work with - the UK’s ground temperature range (excluding Northern Ireland) sees southern England enjoying average ground temperatures of 12.7°C and northern Scotland seeing an average of 8.8°C.

Should you get an air source heat pump or ground source heat pump?

Ultimately, the type of pump you should get depends on your budget, energy needs and the property you’re living in. If you don’t have the space for the network of pipes that come with a ground source heat pump, you’ll have to get an air pump. If you can install either option and can afford to get a ground source heat pump, this is the more consistent and energy-efficient option. However, potential planning permission requirements may scupper getting one. Examine the options carefully before making your decision.

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Published on Tue 02 Mar 2021 04.28 GMT