Ceiling-Mounted – Ceiling-mounted fans are the most common. It’s the perfect location since hot air rises. You can choose a fan, a fan/light combination, or a fan/heater combination.
Exterior-Mounted – Exterior mounted fans have the motor installed outside of the bathroom in the attic or other utility area. This arrangement greatly reduces the noise from the fan motor. A common installation technique uses one fan motor to service several rooms. The duct work from each room is connected in the attic.
Where should an exhaust fan be located?
In a standard size bathroom (5’ x 8’), the center of the room is fine. This will service the bathtub/shower as well as the toilet area. An additional fan will be needed in a larger bathroom, especially if the toilet is compartmentalized. A moisture proof or vapor proof exhaust fan can be installed directly over a tub/shower area. A GFI (Ground Fault Interrupter) circuit is required for this type of installation. Wall fans are the least desirable because they will not exhaust the heat and moisture that rises to the ceiling.
Consider a Timer or Sensor
It’s best to let a fan run for a few minutes after a bath or shower. Leaving a fan on too long wastes energy. Be sure to choose a timer that’s rated for motors, not just lighting. Another choice is buying a fan with a built-in sensor that automatically turns off when the correct humidity level is reached.
Is a fan needed if you have a window?
The only ventilation required in a bathroom by code is a window, but it does not provide air circulation, and it may not be convenient to open a window when it’s cold or rainy. An open window raises privacy issues as well.
A bathroom exhaust fan will provide air circulation that will move the heat and moisture to the outside of the house, reducing the humidity level and making the room more comfortable. The life of paint and wallpaper will be increased, and mold or mildew will be reduced.
Helpful Links
http://www.broan-nutone.com
http://www.hunterhomecomfort.com
https://www.nkba.org