How To Size An Attic Fan

By dispelling hot air from your attic an attic fan can reduce the temperatures of your upper level rooms by 10 degrees extend the life of your roof shingles and cut air conditioning expenses by up to 30 percent.

How to size an attic fan.

The formula above gives an approximate value of the cfm needed for an attic fan. The warm air escapes through the attic and to the attic vents allowing the circulation of chilly air from the windows. Without an attic fan the temperature in your attic can climb to a searing 150 degrees. 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.

Always have a balanced ventilation system. 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. Find the overall air volume of your home. Attic fan size calculator step 1.

Then enter the height at the highest point. Enter the length and width of your attic or ceiling crawl space. Calculate the required cfm air flow. 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.

It helps to cool your home temperatures and the attic by approximately 30 degrees. Some professionals multiply the square feet value with 0 6 instead of 0 7. Whole house fans work on the principle of removing the hot and humid air out of the house. Then click on calculate.

To determine the size of your attic multiply the width by the length of the attic floor in feet. This is a quick rundown of the different types of attic fans their most common features and. Multiply length times. Cfm cubic feet per minute is a measure of the amount of air the fan moves in a minute.

I know the dimensions of my attic space. Multiply the total air volume in cubic feet by 30 which represents a complete air change every 2 minutes. Next multiply the square feet of attic space by 0 7 to get the minimum number of cubic feet of air per. Simultaneously cool fresh air will be pulled through the open windows and circulated through every room effectively replacing all of the air in your home and minimizing your dependence on air conditioning.

How to size attic exhaust vent fans for your home attic size. Measure the length and width of each floor of your home with the tape measure.