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Choosing between air source heat pumps and ground source heat pumps will always come down to a mix of different influencing factors. isoenergy’s Will McCarthy explains what will likely affect the choices made by clients.

Available space
Sometimes it just comes down to how much space you have available outside your home. An air source heat pump only needs a fraction of the outdoor space that a ground source heat pump will. A ground source heat pump will need space for boreholes or a horizontal collector array if possible. If this isn’t available, an air source heat pump will be the only practical option.

Installing a ground source heat pump will likely cost between 30%-60% more than installing and air source heat pump. Therefore, the initial cost of ownership for an air source heat pump is less than a ground source heat pump. However, the running costs of an air source heat pump are going to be higher than that of a ground source heat pump, so the payback period at which a ground source heat pump has paid for itself in savings could be sooner than that of an air source heat pump.

Electrical capacity
Because of the way air source heat pumps work in the UK with our humid weather conditions, we need to install a slightly larger capacity heat pump than we would if installing ground source. This means there may not be adequate electrical capacity on site to install enough air source heat pumps to totally displace the current heating system. This may mean that a ground source is the only option for those with limited electrical capacity. It is possible to install a heat pump to provide some of the heating and top this up with a fossil fuel boiler. It all depends on the circumstances.

The right tool for the right job
In summary, there are a range of factors that will help a client decide to go with one technology over the other. We often find that a client will come to us thinking they want one option then find out through consultation that the other is more appropriate for their application. At isoenergy we don’t promote one specific technology over another. We would rather champion a system that is the best fit for the site, offers the best return on investment and the largest carbon saving for any given application.

If you are interested in understanding what renewable options are right for you, get in touch on 01293 821 345.