The Home Ventilating Institute (HVI) recommends that inchinchthe bath fan be left on 20 minutes after the use of the bathroominchinch to successfully fight the damaging effects of moisture.
A timer such as Fantech's Electronic Pushbutton Timer (Model FD60EM) is the ideal answer.
Simply push 10, 20, 30 or 60 minutes then exit the bathroom. Timer will keep the fan running for the amount of time you specify then turn off automatically
Fantech FD 60EM is also known as FD 60EM , FD60EM