Our company has successfully solved many noise nuisance problems caused by roof extractor fans of both the centrifugal and axial type. On our fan noise reduction page, this picture shows the same roof extractor fan as in the photo above, but with the cowl removed.
It can be difficult to achieve a large sound reduction on fans because they often produce a low frequency drone. Most noise control methods provide little sound reduction at a low frequency. Our specialist solutions often provide much a higher noise reduction than other types of solution and frequently make roof extractor fans inaudible at the nearest houses. We have successfully resolved numerous noise nuisance complaints from residents affected by roof-mounted fans and extractors, even where low frequency noise is the most dominant feature.
We have carried out many projects to reduce roof extractor fan noise, mostly using engineering solutions that were low cost to install. The disadvantage of completing so many sound suppression projects on roof extraction fans is that we often have to clamber up onto a roof. This is not a problem if there is a staircase, but not so easy where we have to carry sound measuring equipment up a vertical steel ladder to reach the roof!