Air-source or ground source heat pump noise control
Where the overall air noise from fans has been reduced using silencers and any low-frequency tonal content has been eliminated using innovative techniques such as aerodynamic noise reduction technology that cuts the noise at source, then the remaining noise is often dominated by vibration from fans and pumps. In that case, the best option for further heat pump noise reduction involves damping key system elements. The INVC has produced a detailed guide to heat pump noise control that includes damping to reduce noise at source.

Heat pump acoustic enclosures
Fan and compressor vibration can be radiated as noise by the enclosure panels. Replace with sound damped steel or apply retro-damping in situ.

Fan and pump mounts
These are often constructed from large, flat steel sheets that behave as very efficient loudspeakers. Add SDS retro-damp dampers to cover most of the flat areas to cut the noise radiated by these components by 10dB or more.