Once you know the minimum recommended cfm requirement compare that with the cfm rating of your existing fan.
Cfm of bathroom fan.
Make sure the fan you choose is powerful enough to ventilate your bathroom.
Bathroom vent fans serve an important function by removing humid air from your home to prevent mold and mildew from forming.
The exhaust fan is designed to manage airflow in bathrooms as large as 85 sq.
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.
To be effective a bathroom fan needs to be powerful enough to completely replace the air in the room about 8 times every hour.
The cfm rating measures the volume of air the fan moves.
To meet energy star minimum standards a bathroom fan must have an efficacy level of at least 1 4 for small fans up to 89 cfm and a level of at least 2 8 for larger fans 90 to 500 cfm.
The effectiveness of the fan will be rated in cfm or cubic feet per minute of air moved.
A large bathroom with a jetted tub a toilet and a shower a common configuration in new homes would need a 200 cfm ventilation fan such as the broan l200 ventilation fan available from.
A bathroom exhaust fan that is rated 50 cfm is ok to use in bathrooms that are 50 square feet or smaller.
A fan that s too small won t remove moisture and odors efficiently and will need to run longer increasing wear on the motor.
The cfm represents the airflow required to completely exchange the air in your bathroom 8 times in one hour.
The hampton bay 80 cfm exhaust fan will reduce moisture in your bathroom to help prevent mildew while running at 2 0 sones.
Standard fan sizing.
The rule of thumb is that you need at least 1 cfm per square foot of room area.
Bathroom vent fans are rated for the amount of air they can move measured in cubic feet per minute or cfm.
The result is the cfm or cubic feet per minute rating required for your bathroom fan.
Standard fan sizing applies to bathrooms that are 100 square feet or less.
Learning how to calculate cfm for a bathroom fan will help you purchase the right size fan for your space.
If you want need.