This Aura Gravity Exhaust Ventilator has a 36 inch in diameter opening to the attic or plenum. It also has a 6 inch tall collar. Model number AV-36-C06 has 1,017 inches of net free area (NFA) and comes with a 46″ x 46″ square shaped flange.
Aura Gravity Ventilators of 16 inch in diameter or larger are considered commercial sized. For those who are looking to ventilate their homes, they are encouraged to view roof vents that are smaller in diameter. Typically vents that are 14 inch in diameter or smaller are recommended.
When exhaust vents have a 6 inch tall collar like this vent does, or greater, (8 inch, 12 inch) they are typically used for flat or low slope roofs. Most roofs have a pitch to them, even roofs that are considered flat. For this exhaust gravity vent to work efficiently, it should be installed on the upper portion of the low slope roof since warm air rises. This particular gravity vent can go on a 0/12 to 5/12 pitch roof. For roofs that are pitched at 6/12 or greater, please notify the sales department when ordering your vents. All vents can be modified to operate up to a 12/12 pitch, even though it would not recommend putting an exhaust vent of this height on such a steep pitch.
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 36 inch Aura Gravity Ventilator, produces 2,538 cfm of air exhaust for attic ventilation.