5 Factors to Consider when buying a Bathroom Exhaust Fan


Purchasing a new bath exhaust fan can an overwhelming decision due in part to the extensive selection available in the marketplace. Opting for an Energy Star Rated exhaust fan will help you achieve significant energy savings and help you narrow your selection. So to help you make an informed decision, here are 5 very important factors that need to be considers when you're choosing the right bath exhaust fan for your needs.


CFM stands for Cubic Foot per Minute and it is perhaps the most important factor in choosing the right sized exhaust fan. CFM tell us you how much cubic foot of air is moved per minute. So the easiest way to to determine the right sized fan for your needs is to approximate one cubic foot per minute (CFM) per square foot of bathroom. So if you bathroom is 50 square feet, you will need a bathroom exhaust fan rated for 50 CFM. The Home Ventilation Institute recommended that for bathrooms that are larger than 100 square feet, you add 50 CFM for each toilet, shower and bathtub and an additional 100 CFM capability for a whirlpool tub.


Some fans have features to help you realize additional energy savings such as Motion Sensing capability which turns the fan off automatically once a person leaves the room. Another useful feature is the humidity sensor which allows the fan to only turn on when moisture is detected. In addition to having a light, some bath fans have a low wattage night light to help you find your way through the room in the dark.


Sones is the measure of the noise level. The higher the Sones , the noisier the fan. A quiet fan will be rated at 1.0 Sone or less. Expect to pay a little extra for a quieter fan.

Duct Size

An exhaust fan has to have proper ducting in order for it to function effectively. Not only does the duct need to be routed to the right place (moist air always needs to be exhausted outside), it needs to be the right size to fit the duct connector on the fan. So be sure to check the duct diameter on the exhaust fan.

Light or No Light

A lot of fans come in with a built in light that utilizes energy efficient lamps. Turning on/off the switch will turn on/off both the fan and light.

There you have it! Keep these 5 factors in mind and you'll spend less time worrying about returning those wrong exhaust fan, and more time enjoying the extra money you'll be saving on energy when purchasing an Energy Star Rated Bathroom Exhaust Fan.

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