I installed a 5 duct fan for bathroom exhaust the total length of duct to outside is less than 6 ft.
Cfm rating bathroom exhaust fan.
Length x width x height x 0 13 minimum.
Why you need to have the proper size extractor fan.
With larger rooms at least one cfm for each square foot is required.
A bathroom that is 50 square feet or less needs a 50 cfm fan.
So if you have a bathroom that is 12 feet long 15 feet wide and 10 feet tall then it has a volume of 1800 cubic feet 12 x 15 x 10 and a cfm of 240.
A second fan may be needed.
The appropriate size fan for a bathroom can replace the room s air.
Otherwise use the appropriate calculation based on the room size.
Bathroom extractor fans are mandatory in any bathroom without a window and still highly recommended in bathroom with windows.
Just remember that the fan needs airflow to do its job.
The bigger your bathroom the higher the cfm rating you ll need.
The result is the cfm or cubic feet per minute rating required for your bathroom fan.
The cfm number should be equal to or higher than the listed square footage of the bathroom an exhaust fan is being installed in i e.
Determine the size of your bathroom with this formula.
Purchase a bathroom fan with the required cfm rating or higher.
Cubic volume 7 5 cfm necessary.
The exhaust fan removes moisture and humidity from your bathroom.
Therefore a bathroom with an area of 70 square feet needs a fan with a minimum cfm rating of 70.
The fan won t even push the damper open even with the spring on the exhaust damper removed.
If the enclosed space is small a 50 cfm fan should suffice.
The duct fan is rated 120 cfm free air.
Another bathroom exhaust fan of the type purchased by commercial establishments pulls 470 cfm at the cost of 8 0 sones.
A fan should have a cfm rating high enough to replace the air in your bathroom at a rate 8 times per hour.
If your bathroom has a toilet or shower area enclosed by a door it s a good idea to install a separate exhaust fan for that area.
Panasonic offers their well known whisperceiling fan in various cfm ratings 50 cfm 80cfm 110cfm 150 cfm.
The formula to calculate bathroom exhaust fan size reads as follows.
After calculating your required cfm make sure to check the rating of any fan your purchase.
Fan ratings typically run between 50 and 110 cfm.
5 x research source a fan with too low of a rating won t remove moisture effectively while buying a fan with too much power may lead to unnecessary noise as more powerful fans tend to.
A fan s ability to move air is measured in cubic feet per minute cfm.
1 panasonic fv 11vq5 whisperceiling bathroom exhaust fan review.