Aura Gravity Ventilator with Curb Mount Flange | 20″ Diameter 4″ Tall Collar | 314 Sq. In. NFA | Model AV-20-C4-CMF


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20 Inch Aura Gravity Ventilator with Curb Mount Flange | AV-20-C4-CMF

The 20 inch Aura Gravity Ventilator with Curb Mount Flange is 20 inches in diameter and has a 4 inch tall collar. The model number is AV-20-C4-CMF and has 314 inches of Net Free Area (NFA). All 20 inch gravity ventilators come with a standard 24″ x 24″ square curb mount flange.

Installation: Best used for low slope and flat roofs on roof curbs

This roof vent has a curb mount flange which allows for easy access to the attic or duct below. In other words, the flange is designed to fit over roof curbs or an existing base of the same diameter. As a result, this gives the vent head extra clearance allowing for installation in all climate zones.

6 inch tall roof curbs are available as well as 12 inch tall roof curbs.

How it Operates:

The Aura Gravity Ventilator works like a roof turbine but with no 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. The Aura Gravity Ventilator removes heat in the summer and moisture from the attic in the winter for year-round ventilation on low slope or flat roofs.

Even the smallest breeze can create exhaust ventilation to draw air out of the gravity vent. Therefore, wind speeds of 11 mph for a 20 inch Gravity Ventilator produces 881 CFM of air exhaust for attic ventilation.

Email the sales team at [email protected] or call at 1-800-ROOFVENT for any questions. If you are looking to determine the pitch of your roof, see the Roof Pitch Diagram.

Aura Gravity Vents are UL Listed and rated up to 50+ PSF or wind pressure above 200 MPH.  Certified by Texas Department of Insurance, Florida State Approved & Conforms to the Standards of CALFIRE.

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Aura Gravity Ventilator with Curb Mount Flange- Technical Drawing Downloads

Product LinkDrawing- UnmarkedDrawing- Cut away and Measurements
AV-20-C4-CMFdwg file icon - click to download CAD (dwg) fileunmarked drawingpdf file icon - click to download pdf filedwg file icon - click to download CAD (dwg) fileCut Away and Measurements drawingpdf file icon - click to download pdf file

Aura Roof Vent - Curb Mount Flange Installation Instructions

Product LinkCMF-Installation Instructions- Flat Roof - pdf
AV-20-C4-CMFInstallation Instructionpdf file icon - click to download pdf file

Calculate number of Model AV-20-C4-CMF Vents Needed for a Given Area

Enter the Width and Length of the attic space you need to ventilate to calculate the area. You may also enter the area directly in the "Area" field. It is not necessary to hit the Return or Enter key (which will refresh this page), just enter numbers in the fields.

Enter width of space to calculate area (or enter Area below)

Enter width of space to calculate area (or enter Area below)

If you know it, you may enter the area directly here

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, the numbers shown below are the number of vents of that size which would ventilate the specified area with both 1/300 and 1/150 rule.

Results Appear Here

*Please note
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.

A Roof Curb below would fit this 20 inch diameter product

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Our products can be painted with a durable baked-on powder coating surface finish.
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Brand: Active VentilationUPC(GTIN): 843951011219 Model AV-20-C4-CMF Category:
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