Progress Lighting bathroom fan with lightBathroom fans may not be sexy, but they are necessary. Exhaust fans remove moisture from the air in what is hands-down the wettest room in the house. By wicking moisture to outside the house, fixtures and walls last longer, mold and mildew growth stops before it can start, and overall air quality is better.

Not all fans were created equal, though, so here are some helpful tips to find the perfect fit:


Since the primary goal of a bathroom fan is to remove moisture from the air, the power level of the motor is where homeowners should focus first by looking at the cubic feet per minute (CFM). To find the right CFM, measure the square footage of the bathroom and find a fan with a matching CFM rating.

Exhaust fans are typically available with CFM measurements of 50 to 110 so a bathroom measuring 10 feet x 8 feet would require a fan with a minimum 80 CFM. Bathrooms with more than one shower head will need a fan with a higher CFM even if the square footage matches a lower rating.


An inescapable fact of bathroom fans is that they’re noisy. The industry standard measurement is actually termed a sone, and fans are rated between one and four sones. A fixture with 1 sone is equal to what homeowners hear from their refridgerator, and a 3 sone is about the same noise level as an office.

Folks typically spend an average of 15 minutes in the bathroom to shower so the fan should only generate the amount of noise homeowners can tolerate for that long.

Mounting options

Bathroom fans can be mounted in three different ways; on the ceiling, on an exterior wall, or in the attic space above the bathroom. It is important to note that all fans must vent to outside the house, otherwise mold and mildew can build in unseen spaces creating potentially dangerous health conditions.

Ceiling mounted is probably the most popular mounting option. Not only does it put the fan on the highest point of the bathroom where moisture tends to rise, but it also gives homeowners more options for extras like a built-in light. In this case, the register is fixed to the ceiling with the motor just above and connected to ductwork that vents through an exterior wall or the roof.

Wall mounting means the fan is mounted on an exterior wall so moisture is pulled through and right outside.

In-line mounting is the quietest option of the three because while the register is flush-mounted against the ceiling, the motor is located away from the bathroom, usually inside upper attic space. In-line mounting does provide the benefit of multiple exhaust points, unlike ceiling or wall mounted fans.


Bathroom fans are nearly as customizable as any other fixture. Night lights can be a nice built-in feature to help kids of all ages find their way in the dark, while heaters and and timers can also be handy. Because it usually takes 15 minutes to completely clear the moisture from a bathroom, timers should be set for 20 minutes after the end of a shower.

The 15-minute rule is also why bathroom fans should not be linked to the same switch as the room’s light fixtures; the light usually gets turned off before the fan has fully done its job.