How Much Cfm Do I Need For Attic Fan

17600 cubic feet 1600 11.

How much cfm do i need for attic fan.

Proceed to step 2 and use the chart to determine the size and number of solar powered attic ventilation fans required to achieve a min. Cfm cubic feet per minute is a measure of the amount of air the fan moves in a minute. Divide the cubic feet measurement by the cfm rating assigned to the fan. Ideally there should also be plenty of soffit intake space their calculations recommend 336 net square inches of open soffit ventilation to supply 700 cfm.

What this means is that every eleven minutes the air in the home is being exchanged by a fan of this rating along with having windows open in each room. 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. You need a minimum of 1 square foot of attic air venting for each 750 cfm of air flow. Attic vent fans are commonly rated from 800 to 1 600 cfm making one fans suitable for attics of up to around 2 200 square feet.

Use the chart below as an attic vent fan cfm calculator. Ventilation rate of 10 air changes per hour. Ft of attic space for example 20 x 50 to be effective. The formula above gives an approximate value of the cfm needed for an attic fan.

If you need 6 000 cfm of air flow through your house divide 6 000 by 750 to get a minimum 8 square feet of. According to the home ventilating institute hvi powered attic ventilators need to move a minimum of 700 cubic feet per minute cfm for 1 000 sq.