EXHAUST FANS PDF Print E-mail
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Wednesday, 06 January 2010 00:25


Exhaust fans come in a variety of sizes and styles. You may have exhaust only or combine it with a light source or a heat/light source. Exhaust fans are rated in two ways. CFM (cubic feet “of air” moved per minute) and sones ( a unit measurement of sound). The more CFM, the more air movement. The less sones, the quieter the fan. Keeping your budget in mind, the higher CFM’s and lower sones equals higher fan cost. The N.E.C. requires any bathroom without a window and any laundry room without proper ventilation to have an exhaust fan. Our expert electricians can help you to choose the right size and proper location for you exhaust fan. See design tips.

Design tips….

 The NEC requires there to be 8 exchanges of air per hour.

The formula for calculating the proper size exhaust fan for a bathroom is

 
7.5 X total volume of the bathroom.

 
So, for a bathroom 7’ wide by 6’ deep by 8’ high

 
7’ x  6’ x  8’ = 44.8 sq. ft.

 
A 50 CFM fan would work fine in a bathroom of this size.

 
There is no N.E.C. requirement for the location of an exhaust fan in the bathroom or laundry room. They can be placed on the ceiling or on the wall. It can be mounted over a shower or tub if the unit is GFI protected. In most cases, the unit is installed in the center of the room.

 

Last Updated on Wednesday, 06 January 2010 00:34