How To Size An Attic Fan

Attic fan size calculation.

How to size an attic fan.

Cfm cubic feet per minute is a measure of the amount of air the fan moves in a minute. This attic ventilation calculator computes the size and number of solar powered attic fans to achieve the proper ventilation for your attic. A whole house attic fan is installed in the ceiling between the top floor and the attic as a supplement to air conditioning. How to size a whole house attic fan.

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. 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. The whole house fan is installed inside the attic between the living space and ceiling.

It helps to cool your home temperatures and the attic by approximately 30 degrees. The formula above gives an approximate value of the cfm needed for an attic fan. 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.

Whole house fans work on the principle of removing the hot and humid air out of the house. It s also important to have plenty of soffit or gable vents for the fan to draw air into the attic. This will help to avoid premature damage to the shingles or mold building up in moist hot. The warm air escapes through the attic and to the attic vents allowing the circulation of chilly air from the windows.

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. 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.