Residential Exhaust Fan Size Chart

I am now a believer in powered attic ventilation.

Residential exhaust fan size chart.

A ventilation fan should meet at least the minimum size. Bathroom vent fans serve an important function by removing humid air from your home to prevent mold and mildew from forming. A range hood fan should move a minimum of 100 cfm of air for every 12 inches of stove width. Sizing for large bathrooms for bathrooms over 100 square feet exhaust fans can be sized according to the number of fixtures in the room.

Everything in a range hood starts with a quality fan. Well managed indoor air quality is crucial to code compliance. Use this table to calculate the cubic feet per minute cfm capacity needed for an exhaust fan in a specific room. 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.

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. 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 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.

The effectiveness of the fan will be rated in cfm or cubic feet per minute of air moved. Air change rate calculate air change rates equations in imperial and si units. 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.

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. Our installer friendly energy star ventilation solutions help you design beyond code without compromising interior aesthetics. Learning how to calculate cfm for a bathroom fan will help you purchase the right size fan for your space. Fan size and quality.

Garage ventilation exhaust ventilation from garages and workshops. 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.