"It replaced an old 6" fan used to extract air from a small cloakroom - the only ingress of air was from a 1/2 inch slit under the door so it has to work hard.
Basically (a) it does its job well, (b) was easy to install, (c) is quiet enough ( not wisper quiet but quiet enough and no audible blade whine) (d) looks OK (e) the back draft shutters work (f) it is simple - just an induction motor and a heated capsule driving the back-draft shutters. (g) double insulated so doesn't need an earth and so shouldn't upset sensitive RCCD's in the consumer unit !! (h) it was reasonably priced
Now all we need to know is how long it lasts ?
(the original fan was over 20 years old and was only replaced because of the blade whine)"