Bathroom Fan Sizing

Donald vail august 25 2018 at 8 36 am.

Bathroom fan sizing. The second fan is 150cfm with the ability to have a 4 or 6 vent pipe attached. Bathroom fans improve indoor air quality by venting moist air quickly outside which eliminates problems associated with high humidity like mold and mildew growth steamy mirrors and peeling wallpaper and paint. Never vent a bathroom fan directly into an attic it must always vent outside.

If your bathroom has an 8 ceiling the cfm rating for your fan should be as least as high as the number of square feet 5 x 7 35 sq. To be effective a bathroom fan needs to be powerful enough to completely replace the air in the room about 8 times every hour. A lower rating means a quieter fan.

For example for a 50 79 sq. For example a fan with a sone rating of 1 or less operates at about the sound level of a refrigerator. The bathroom has a separate toilet room.

Why you need to have the proper size extractor fan. The minimum allowed fan size is 50 cfm so if your bathroom is for example only 42 square feet you still need a 50 cfm fan. Small room bath fans perfect for a modest sized bath or powder room.

The effectiveness of the fan will be rated in cfm or cubic feet per minute of air moved. Cubic volume 7 5 cfm necessary. The higher the bath fan rating the more air can be vented out of the bathroom which means less moisture and mold build up.

Learning how to calculate cfm for a bathroom fan will help you purchase the right size fan for your space. Bathroom select a fan with a 50 to 80 cfm rating. The formula to calculate bathroom exhaust fan size reads as follows.