Vent CalculatorDesign Your Balanced Ventilation System.

All Lomanco attic ventilation product requirements are based on the minimum standard 1/300 rule as set forth by the International Building Code (IBC) and the International Residential Code (IRC). If local code requires the 1/150 rule, please double the requirements. Lomanco foundation ventilation product requirements are based on the 1/150 rule.

Choose your exhaust system and enter area to ventilate. (Attic floor space in square feet.)

 
ENTER AREA TO VENTILATE:
' sq ft.
*Pick Your Roof Slope:
* Slope input is only used in A series and 900 series style gable vents.
Required Exhaust NFA(1/300 Rule):
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