Attic Fan Sizing Calculator

Calculate or enter the square footage of the attic or area to be vented.

Attic fan sizing calculator.

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. This calculator is designed to arrive at a reasonable attic or ceiling crawl space ventilation fan air volume displacement rating for minimum normal and optimum outside heat conditions. The formula above gives an approximate value of the cfm needed for an attic fan. 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.

If you do this you don t need to enter a length or width. Attic x 0 7 700 cfm minimum fan rating add an additional 20 cfm x 1 20 if you have a steep roof and 15 cfm x 1 15 for a dark roof. 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. 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.

Attic fan size calculator this attic ventilation calculator computes the size and number of solar powered attic fans to achieve the proper ventilation for your attic. Use this estimator to help figure out how many attic fans you will need. Attic fan size cfm 0 7 x sq ft area of the attic formula 1 the size of an attic fan is calculated in terms of cfm. Help determine optimal sizing of solar attic fans.

Alternatively for more precise calculations you can provide your actual floor area. Let owens corning roofing help you calculate exactly how much ventilation you will need for a healthy and balanced attic with our 4 step ventilation calculator. Next multiply the square feet of attic space by 0 7 to get the minimum number of cubic feet of air per minute that the fan should be rated to move. Cfm cubic feet per minute is a measure of the amount of air the fan moves in a minute.

By sizing and implementing a whole house fan you can pull the warm stale air from your entire home into the attic where it s vented outside. How to size solar attic exhaust vent fans so we developed our solar powered attic fan sizer calculator. Attic fan ventilation calculator this calculator requires the use of javascript enabled and capable browsers.