Considering the well-documented rise of gas bills in the UK, businesses across the country are debating whether to replace their gas boilers with other heating systems. One of the most commonly discussed alternatives is that of heat pump technology. We’ve talked about commercial heat pumps in the past, but there’s a key topic that keeps cropping up we want to address.
There are two main types of heat pump available in the UK, called ground source and air source heat pumps. When considering a new heating system, understanding what each is and the difference between them is important. Both offer advantages and disadvantages, some of which will be more applicable to your business and premises than the other.
So with that in mind, which is better, ground source or air source heat pumps?
Ground source heat pumps
How they work
Ground source heat pumps use the thermal energy available in the ground to deliver heat. Systems are built using a loop of pipework filled with water and antifreeze, which is circulated around, absorbing heat. This heat causes the water and antifreeze mixture to expand and become a gas, which is then passed into a compressor. The gas is compressed, increasing the temperature so that heat is released over a heat exchanger to create hot water, which is pumped to radiators or taps like a standard boiler.
When comparing heating systems, you need to consider the location of the system and time of year. A ground source heat pump has access to more stable forms of heat, because UK ground temperature varies less than air temp. Soil remains at 5C or higher throughout the year, rarely falling below freezing.
This stable temperature means that while ground source pumps are often less efficient than air source during warmer months, they tend to offer more stability in terms of efficiency.
Due to the nature of ground source pumps, installation involves choosing whether to house horizontal or vertical pipe loops in your outdoor space. Vertical pipes take up less space and require boreholes, whereas horizontal pipes take up more space so they’re only relevant to businesses that own enough exterior land. You’ll need an internal unit too, but they tend to be about the same size as a boiler so if you’re replacing yours it can likely use that space.
Air source heat pumps
How they work
Air source heat pumps are similar to air conditioners in their function, in that an exterior unit brings in ambient air that causes the refrigerant gas contained in the pipework to evaporate. This gas is then rapidly compressed, creating warm high-pressure vapour that passes a heat exchanger, heating hot water to be used for heating and taps.
Air source pumps are more variable in terms of efficiency because of the heavy fluctuations in air temperature here in the UK. While air source pumps still provide heating even in cold days where the temperature drops below freezing, they are more efficient during warmer months. In peak summer, they can be far more efficient than ground source pumps.
Air source pumps require less complex installation processes. An installer has to fit suitable exterior pump units which look like traditional air conditioning condensers. Some systems, especially commercial ones, will have an interior unit too which is a similar size to a normal gas boiler.
Which is better?
With all of the above said, is there a clear winner between ground-source and air-source heat pumps? Unfortunately, as much as we’d like to point to an easy answer, there isn’t one: the system depends entirely on your business and intended usage. If you’re in a colder part of the UK and have plenty of outdoor space free of trees and other obstructions, a ground source system may be ideal. If you’re a smaller business further south and have access to better air temperatures, air source pumps may be better.
Rather than worrying about which is right for you, why not contact our team? We’ll talk you through the options and discuss your needs to determine the best heating system for your business.