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CFM for bathroom ceiling fan

Should the cfm on a bathroom fan be higher in a high use bathroom, or is the size of the bathroom the only factor?
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Posted 2017-10-22T19:58:12+0000  by Lee123 Lee123

Hey Lee123,

Thanks for your question and welcome to the community.

According to our Buying Guide for How to Choose a Bath Fan:

A fan’s ability to move air is measured in cubic feet per minute (CFM). The bigger your bathroom, the higher the CFM rating you’ll need. A fan should have a CFM rating high enough to replace the air in your bathroom at a rate 8 times per hour. 

Determine the size of your bathroom with this formula: Length x Width x Height x 0.13 = Minimum CFM rating

If all else fails, check the packaging. Each bath fan will indicate the maximum square footage it can't ventilate.

Most fans are rated from 50 to 110 CFM. 

  • For bathrooms 50 square feet and smaller, it is recommended you purchase a bath fan designed for small rooms, which will typically have a CFM range of 50-79.               
  • For bathrooms that are larger, select a fan that can move at least 1 CFM per square foot of room. So, for an 80 square foot bathroom, select a fan with at least an 80 CFM rating.

For this and any other additional questions, please do not hesitate to ask us.


Posted 2017-10-23T16:04:49+0000  by Joseph_HD_ATL
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