Aura Gravity Ventilator | 18″ Diameter 2″ Tall Collar | 254 Sq. In. NFA | Model AV-18-C2


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This product has UL Certification. Check out other details and specifics on UL Product IQ™ (Note: UL now requires you to have a free account to access this page) UL’s Online Certifications Directory.


18 inch Roof Vent | Aura Gravity Ventilator | Model AV-18-C2

The 18 inch Aura Gravity Ventilator is 18 inches in diameter and has a 2 inch tall collar. The model number is AV-18-C2 and has 254 inches of Net Free Area (NFA). All 18 inch gravity ventilators come with a standard 23″ x 23″ square flange flashing.


  • Keeps your home comfortable and energy efficient
  • Inner louvers prevent insects and animals from entering the vent
  • Round aerodynamic design can withstand harsh weather and wind forces beyond 200 mph
  • Vent head is removable for easy installation
  • Noiseless – does not require electricity to exhaust air

Where to Install:

If installed no more than 3 feet from the peak, this roof vent can go on a roof with a pitch of 3/12 to 7/12. However, with modification, this vent is capable of installment on a 12/12 pitch in all climate zones. See the installation guides for help installing.

The Aura Vent is ideal for ventilating steep slope roofs. It will remove heat during the summer and moisture during the winter to provide ventilation all year. Keeping the attic dry and cool during the winter will preserve attic insulation and prevent ice dams.

18 inch diameter roof vents are considered commercial size and therefore should be used in commercial settings. For those looking to ventilate their homes, please view roof vents with a smaller diameter.

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 which occurs when the wind blows against the outer louvers. It creates a spinning upward draft through the vent allowing air to dynamically flow out of the vent. Even the smallest breeze can create exhaust ventilation to draw out air from the vent.

The Aura Gravity Roof Vents are made of durable rust-free aluminum. The vent head has a flat one-piece spun lid that prevents rain and snow from entering the vent. The round aerodynamic design can withstand harsh weather and wind forces beyond 200 mph. Therefore, wind speeds of 11 mph for an 18 inch Gravity Ventilator produces 634 CFM of air exhaust for attic ventilation.

The inner louvers of the roof vent prevent insects and animals from entering the attic. The louvers also allow the air to flow freely to the outside.

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

For any questions please see the frequently asked questions page. If you still have questions, email the sales team at [email protected] or call 845-565-7770.

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Click below to see or download full Installation Instructions for this product

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Calculate number of Model AV-18-C2 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.

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Brand: Active VentilationUPC(GTIN): 843951000640 SKU: AV-18-C2 Category:
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