The Aura Gravity Roof Ventilator removes heat from the attic in the summer and in the winter. This allows for year-round ventilation. It functions like a spinning roof turbine but without any moving parts. Aura Gravity Ventilators rely on the Venturi Effect when the wind blows against the outer louvers. As a result, this creates an upward draft allowing air to freely flow in and out of the vent. 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).
The Aura Gravity Ventilator also ventilates the roof through “The Stack Effect”. This is when hot air naturally rises out through the roof vents.
The Aura Vent with Curb Mount Flange is designed to fit over Roof Curbs. This allows for additional height to protect the vent. In addition, it also allows for installation on flat roofs.
The 1/8 inch louvers are designed to prevent precipitation and wildlife from entering inside the vent.
The curb mounted flange design allows for easy access for maintenance of the attic, fan, or duct below.
Net Free Area
in Sq. In.
|4" Collar||6" Collar||8" Collar||12" Collar|
The diameter size of all roof vents determines the Net Free Area, also known as the "NFA". NFA is the measured amount of opening each vent offers at each specific size. to be available for venting air through a specific vent size. The calculator below will find the overall number of vents needed to effectively ventilate the targeted attic space.
Once you have the area, pulldown to select the specific vent diameter to show the number of vents of that size which would ventilate the specified area with both 1/300 and 1/150 rule.
The roof vent calculation values shown above are for the exhaust portion of the roof. The same amount of net free air inches is needed for air intake as well. Proper roof ventilation consists of 50% air exhaust and 50% air intake.