More Bathroom Fan Tips
Lenght of time a bath fan run after a shower is used? The Home Ventilation Institute recommends that a fan should be left on for 20 minutes more to clear humidity adequately and to ensure moisture and condensation in the fan body or ducting is minimize
Location of a Bathroom fan
Exhaust fans should be located in or near the shower or tub, and in an enclosed water closet. Keep exhaust points opposite the supply air source to ensure that the fresh air is drawn through the room. Bathroom doors should not be sealed too tightly at the bottom in order to allow "makeup air" to enter the room when the door is closed.
Why do the windows and mirrors fog even when the fan is running?
If windows and mirrors are very cold, condensation can still form on these surfaces. And if your bathroom is sealed tightly, replacement air may not be entering the room fast enough to displace the moist air. Be sure to undercut your door sufficiently to draw fresh air into the room. Fan placement can also be a factor. Your fan should be located far from the replacement air source to ensure the moist air is drawn out first. Finally, too many twists and turns in the ducting will significantly reduce the ability of the blower to remove moist air. Make sure your ductwork is as short and straight as it can be, with gradual turns rather than tight corners where necessary.