The noise from heat pumps, be they air-source or ground-source units, often poses a serious problem as not only can they be loud, but they are also installed very close to or on noise-sensitive premises.
The result: noise complaints
Unfortunately, current heat pump noise specifications and limits are often inadequate as they do not take into account the common low-frequency tonal nature of the noise generated by many heat pumps.
Mis- (or no) diagnosis of the characteristics of heat pump noise is extremely common, leading to money wasted on noise control measures that are either ineffective or that reduce efficiency - or both. Our experience indicates that a substantial proportion of the noise mitigation measures applied to these units (acoustic enclosures, attenuators, barriers) are either over-engineered or ineffective as they address the wrong problem. This is supported by the fact that the Environment Agency and EHO surveys indicate that 95% of noise reports are inadequate.
There are 2 categories of noise generated by heat pumps:
The latter cannot be addressed using the silencers and barriers so often installed due to simple physics. Moreover, these can reduce system efficiency.
A few minutes with a smartphone is all that is required to carry out the proper diagnosis to determine and rank the noise sources and hence to the optimum noise control options. Anyone can do this.
This approach dramatically reduces the costs of typical noise reduction projects and can even simultaneously improve system efficiency.