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February 24th 2023

Air source and Ground Source – What’s the difference?

Choosing a suitable heat pump system for your property isn’t a 2 minute job, as any financial investment needs to be well thought out and weighed up, including both the pros and cons. For heat pumps, there are various different factors that may help determine what system is right for you, and may even make the decision for you.

In this blog post, we explore the key differences between the two most common types of heat pumps, air source and ground source, and give a comparison to help you make a more informed decision to what renewable heating solution is best for you and your property.

How they work

To put it simply, both air and ground source heat pumps work in the same way, the refrigerant picks up heat from the ground or air via a heat exchanger installed in the heat pump.  The compressor then takes this heated refrigerant and compresses it creating a high pressure in the refrigerant which in turn raises the temperature of the refrigerant further.

This heat is then transferred into the water used in the heating or hot water system via another heat exchanger. The temperature of the cooler return water from the heating or hot water system is then added to the refrigerant, which returns to the ground or air heat exchanger, picking up more heat and this process is then repeated.

The cost 

Air source heat pump

Typical costs for a domestic air source heat pump system is between £12,000 – £16,000, and would normally include a new domestic hot water cylinder and buffer cylinder.

It’s worth being aware that some radiators might need upgrading to work at the lower flow temperatures provided by heat pumps and would incur extra costs.

Ground source heat pump

Typical costs for a domestic ground source heat pump installation is between £25,000 – £45,000, and would include a new domestic hot water cylinder, buffer cylinder, ground/drilling works involved with installing the ground collector.

And some radiators may also need upgrading to work at the lower flow temperatures provided by heat pumps that would incur extra costs.


Ground source heat pumps are generally more efficient than air source heat pumps due to the ground temperature being more stable throughout the year, the colder the source temperature from the ground or air, the more electrical energy the heat pump needs to generate the same amount of heat.

Installation requirements

Air source

Air source heat pumps need space for an external heat pump unit, this can be mounted on the ground or wall and is then connected to the internal heating components via pipework and electrical cables. Cylinders are generally larger than that of more traditional heating systems so extra space may be required to site these along with the requirement of extra pipework.

Air source heat pumps are typically better suited to small to medium sized domestic or commercial properties due to the reduced size of the equipment required as opposed to a ground source heat pump.

Ground source

Ground source heat pumps generally will need a specific room to install the equipment, the cylinders used along with the heat pump unit itself are much larger and would usually be installed in an outbuilding or specific room in a property for the heat pump and equipment.

The electricity supply for larger ground source heat pumps would need to be a 3 phase supply.

Ample land outside is also required as ground collector pipework would be required, this is generally installed horizontally by laying plastic pipework at a depth of 1m and 1m apart and on a smaller heat pump would use approx 600m of pipe work.

The ground collector can also be installed vertically by drilling down into the ground to depths of up to 100M (depending on the geology of the area) and this would require less land however good access is required for the drilling equipment and the installation cost is greatly increased.


Heat pumps are a great way to provide low carbon heating to any property type if designed well and installed by an experienced heat pump installer.

As a rule of thumb, Air source heat pumps are probably the best choice for a small to medium sized property and ground source heat pumps for larger properties, although we have installed both types in all scenarios.

A heat pump can be installed in any type of property regardless of age or insulation levels, however the better your insulation, the lower the installation cost and in turn the lower the running costs will be.

If you’re still unsure what system would be best for you and your property, get in touch and speak with a qualified heat pump engineer today!  Or if you’re ready to make the switch to renewable heating solutions, call 01603 406052 or get in touch via our website and start your journey to green heating with Heat Different.