Calculating Attic Size

Input length width and desired r value of the area to be insulated.

Calculating attic size.

This attic ventilation calculator computes the size and number of solar powered attic fans to achieve the proper ventilation for your attic. 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. Pitch measurement method 2. We also need to allow for the floor system in our calculations.

Measure the height of your attic in feet. How to size attic exhaust vent fans for your home attic size. Make sure to measure in the center at the attic s highest point. The formula above gives an approximate value of the cfm needed for an attic fan.

Click to see full size image. If this distance measures 4 inches you have a 4 in 12 pitch. 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. Click the button to calculate the depth in inches and pounds of total insulation required for this job.

Divide this number by two. Next multiply the square feet of attic space by 0 7 to get the minimum number of cubic feet of air per. So draw up a simple cross section showing the outside wall a rafter set at the correct pitch and a floor system. Cfm cubic feet per minute is a measure of the amount of air the fan moves in a minute.

This calculator is to be used as an estimating tool only. Measure the length of your attic in feet. Calculate or enter the square footage of the attic or area to be vented. Measure the length and width of the attic floor space to be ventilated.

8 inches and you have an 8 in 12 pitch. I ll do this on the right side of the house which is a 12 12 pitch. How to calculate the cubic feet of an attic. To determine the size of your attic multiply the width by the length of the attic floor in feet.

Measure the width of your attic in feet. Next we need to calculate the 5 and 8 ceiling lines. The word denotes the framing or composition which helps that covering also.