Calculating Attic Volume

Remember the minimum area requirement when using a continuous system is a ratio of 1 300.

Calculating attic volume.

Whether you plan on improving the ventilation in your attic or adding energy saving insulation you will need to accurately determine its actual size. 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. Then enter the height at the highest point. 1 500 square feet 300 5 square feet.

Ok so now we know the square footage of the attic area to be ventilated. How to calculate the cubic feet of an attic. Divide this number by two. Enter the length and width of your attic or ceiling crawl space.

Ventilation manufacturers assign an nfa value to the non motorized vents they make. In order to find the right calculator divide the attic floor space by 300 sq feet. Nfa is the unobstructed area through which air can pass through a vent usually measured in square inches. Measure the height of your attic in feet.

Make sure to measure in the center at the attic s highest point. 1 cubic foot is 12 x 12 144 cubic inches. Next multiply the 4 square feet into cubic inches. In our case the required 4 vents for the 1200 sq ft house multiply the 144 cubic inches by 4 576 cubic inches.

Select if your roof is more flat of peaked. Use a tape measure to figure out the dimensions of your attic. Then click on calculate. For heating and air conditioning airflow or for other exhaust fan situations see our airflow calculator.

See how simple that was. Measure the length of your attic in feet. So in our example we will divide the 1 500 square feet by 300. Measure the width of your attic in feet.

Now let s figure out how much ventilation space we need. Calculate or enter the square footage of the attic or area to be vented. Attic square footage 2 square inches of exhaust and square inches of intake net free area nfa needed. Input length width and desired r value of the area to be insulated.

Measure the length and width of the attic floor space to be ventilated. Square footage relates to the floor area only and does not factor in the height of the attic space.