Fan is clearly audible at low speed & is quite noisy at boost - I'm glad I have a manual pull cord to keep it at low speed unless the shower is/has just been on.
I wouldn't put this in an en-suite because it might still be audible at low speed even with the door shut.
It does keep steam levels down when showering and on boost speed. Note that even with the heat recovery - the incoming air feels cold - I've yet to take actual temperature readings though.