Choosing between Ground and Air Source Heat Pumps – what should you consider?
Performance – except in very special cases a GSHP system will always offer better performance than an ASHP. This results in significantly higher carbon savings and lower running costs.
Reliability – A GSHP system will be more reliable and have lower maintenance requirements than an ASHP as it has fewer moving parts.
Design Complexity – The variable output and efficiency of an ASHP (both are proportional to the outside air temperature) means careful system design is needed. If this is overlooked, then the system will perform poorly. The output and efficiency of GSHP systems is much more predictable.
Noise – The fans of an ASHP system make a noise which can be a problem for building occupants or neighbours. Full planning permission is required for these systems as a result. GSHP’s need no planning permission.
Visual Impact – A GSHP system has no visual impact once installed. ASHP systems are usually sited outdoors and are relatively large compared to an equivalent GSHP unit. Space needs to be found for the ASHP plant.
Renewable Heat Incentive – Although the final details are yet to be confirmed the proposed Renewable Heat Incentive payments are likely to be lower for ASHP systems, certainly in the non-domestic sector. This could massively impact the financial payback compared to a GSHP system.
Cost – The lack of a ground collector means that an ASHP system will be cheaper to install than a GSHP equivalent. After taking into account all the items above however, the choice becomes a lot less clear cut. With our extensive experience of both technologies we can advise on the most appropriate choice for your project.
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