Back in April 2009 we got a 4" fan fitted in our bathroom in order to reduce condensation, mould etc as this was becoming more of a problem since we got our nice new powerful shower. However this didn't really make a difference and I think it may be the fan which is at fault because someone conned us saying he installs good quality fans but instead installed a cheap £15 one, the fault with it is that the air operated internal shutter only opens when there is absolutely no breeze because the force from the fan is not able to keep the shutter open.
There is a gap under the door and a trickle vent on the window, the room is 4.5mx4.5m.
Will replacing the fan for a better one (Vent Axia) which actually as thermo shutters or whatever its called do the trick? When there is no breeze the fan apart from being very noisy does keep the steam levels quite low.