The Aura Gravity Exhaust Ventilator has a 30 inch in diameter opening (throat) to the attic or plenum. It also has a 12 inch tall collar that provides a 12 inch clearance between the roof and the gravity vents louvers. Model number AV-30-C12 has 706 inches of net free area (NFA) and comes with a 40″ x 40″ square shaped flange.
The Aura Gravity Ventilator, size 30 inch in diameter is considered an industrialized sized roof vent. For those who are looking to ventilate their residential home, they are encouraged to view roof vents that are smaller in diameter. Typically roof vents that are 14 inch, 12 inch, 10 inch and 8 inch in diameter are commonly used for residential attic ventilation.
When exhaust vents have a 12 inch tall collar, they are typically used for flat or low slope roof applications. Exhaust gravity vents work best when installed on the upper portion of the low slope roof since warm air rises. The Aura Gravity Vent can go on a 0/12 to 5/12 pitch roof for zones 1 through 8, meaning these tall gravity vents can be installed in all climates, including those that are persistently cold or are in high alpine areas.
The Aura Gravity Ventilator is engineered to withstand long seasonal snow packs and frequent snow storms that may drop a foot or more of snow and still remain functional.
The Aura Gravity Ventilator works like a roof turbine but with no moving parts.
Aura Gravity ventilators rely on the Venturi Effect (the creation of an upward draft) when wind blows against the outer louvers.
Even the smallest breeze can create exhaust ventilation so that air is drawn out of the gravity vent. This movement of air is proportional to the wind speed, and is measured in cubic feet per minute (CFM). Wind speeds of 11 mph for a 30 inch Aura Gravity Ventilator produces 1,692 cfm of air exhaust for attic ventilation.