Bathroom extactor fan

[CONFUSE]

Hi I am wanting to update my extractor fan in my bathroom (it has no windows).I am wondering if anyone has any recommendations on the size of fan reqd,i am looking at installing a ceiling extractor with a roof vent .The bathroom is approx 3mx3m.I currently have a 6" wall fan.

 

[bathjobby]

Just look at the specification on the packaging (lots in the DIY sheds or online) and see what volume of air per minute they move and decide if thats suitable for your size room e.g. if your room is x cubic meters and the fan will vent x/2 meters per minute, then are you going to be satisfied with a complete air change every 2 minutes ! Your call, if not get one that shifts more... Always worth paying the extra for a low noise one though - 44db or preferably lower.