Residential Exhaust Fan Size Chart

Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge.

Residential exhaust fan size chart.

Blower fans that resemble hamster wheels outperform fans with blades also known as impeller fans. To be effective a bathroom fan needs to be powerful enough to completely replace the air in the room about 8 times every hour. Use this table to calculate the cubic feet per minute cfm capacity needed for an exhaust fan in a specific room. Well managed indoor air quality is crucial to code compliance.

Garage ventilation exhaust ventilation from garages and workshops. Vent fans are rated by the number of cubic feet of air they move per minute cfm and it s important to buy a large enough fan for the size of your bathroom. A range hood fan should move a minimum of 100 cfm of air for every 12 inches of stove width. Ventilation systems for ventilation and air handling air change rates ducts and pressure drops charts and diagrams and more.

A fan sized using the above formula would cause 10 to 30 air exchanges per hour depending on the height of the attic more than the recommendation for a steam filled bathroom. A ventilation fan should meet at least the minimum size. This fan calculator is typically used to calculate the cfm or cubic feet per minute of air exchange that may be desired in a building. However i think the fan sizing above is excessive.

Our installer friendly energy star ventilation solutions help you design beyond code without compromising interior aesthetics. The effectiveness of the fan will be rated in cfm or cubic feet per minute of air moved. 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. Learning how to calculate cfm for a bathroom fan will help you purchase the right size fan for your space.

Fan size and quality. Whether exhausting air or bringing fresh air into a structure the calculation produced should help to figure out the size of fan s required to accomplish the air exchanges needed. Bathroom vent fans serve an important function by removing humid air from your home to prevent mold and mildew from forming. Everything in a range hood starts with a quality fan.

Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space. Infiltration heat loss from buildings estimated infiltration heat loss.