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Aura Gravity Ventilator | 42″ Diameter 4″ Tall Collar AV-42-C04


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Basic dimensions of the Aura Vent and it’s identifying attributes. Primary identifying dimensions of vents and fans are the inside diameter of the Head, which equals the diameter of the hole being vented, and the height of the Collar which is the solid tube between the Head of the vent and the Flange which attaches to the roof.

Inside Diameter:

42 in.
106.7 cm.

Outside Diameter:

48 in.
121.9 cm.

Square Flange (side length):

52 in.
132.1 cm.

Height of Head:

18 in.
45.7 cm.

Collar Height:

4 in.
10.2 cm.

Height of Flange:

0 in.
0 cm.

Total Height with Collar and Flange:

22 in.
55.9 cm.

Louvers are the vertical openings in the vent, which facilitates the flow of air, while keeping animals, insects, debris, and embers out.  The combination of inner and outer Louvers on our signature “Aura” series of vents and fans are shaped to create a positive vacuum effect which draws air out of the vent, utilizing a physical principle known as the Venturi effect.

Louver Height (inside):

14.5 in.
36.8 cm.

Louver Height (outside):

14.5 in.
36.8 cm.

Size of opening btwn blades (inside):

0.5 in.
1.27 cm.

Size of opening btwn blades (outside):

0.5 in.
1.27 cm.

Expected snow and rain in your region and the pitch of the roof are the key consideration when choosing the height of the collar of your roof vents. Zones 1 and 2 are not expected to sustain significant snow packs, while zones 3-7 are likely to experience snow, possibly for weeks or months. Vent collars under 4 inches are inappropriate for flat (0/12 pitch) roofs because even heavy rain can splash water into a shorter vent.

Map of Climate Zones

Minimum Pitch Capacity:

0/12 - 0°

Maximum Pitch Capacity (Standard Vent):

3/12 - 14°

Maximum Pitch Capacity (Modified):

12/12 - 45°

Free Air Space:

1385.4 sq. in.
8938.3 sq. cm.

Free Air Space:

9.6211 sq. ft.
0.8938 sq. m.

1:150 Ventilation Rule:

2886.34 sq. ft.
268.15 sq. m.

1:300 Ventilation Rule:

5772.68 sq. ft.
536.299 sq. m.

The Venturi effect stimulated by even small breezes creates a positive movement of air out of the vent without the need of any part of the vent to move. This movement of air is proportional to the wind speed, and can be measured in Cubic Feet per Minute or Cubic Meters per Minute.

4 MPH Wind:

1883 CFM
Airflow in 6.4 KPH Wind: 53.32 CMM

5.2 MPH Wind:

1931 CFM
Airflow in 8.4 KPH Wind: 54.68 CMM

7.4 MPH Wind:

2960 CFM
Airflow in 11.9 KPH Wind: 83.82 CMM

9.8 MPH Wind:

3331 CFM
Airflow in 15.8 KPH Wind8: 94.32 CMM

11 MPH Wind:

4997 CFM
Airflow in 17.7 KPH Wind8: 141.5 CMM

Installation Guides Under Development. Coming Soon.

Our Aura Vents have 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.

Texas Department of Insurance - Letterhead

Link to TDI Approval Document, from their web site

Texas Department of Insurance - Evaluation Program

Texas Department of Insurance - Aura Vent Chart

Click the Logo to see the full documentation of Active Ventilation Products approvals on the Florida DBPR web site.
Florida Approval

Active Ventilation Products Aura Vent series has been tested and approved by the State of Florida

Actual Package Weight 70 lbs
Dimensions 52 × 52 × 24 in
UPS Dimensional (Billable) Weight 467 lbs

Active Ventilation Products

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This Aura Gravity Ventilator has a 42 inch diameter opening and a 4 inch tall collar. The AV-42-C04 has 1,384 inches of net free area (NFA) and comes with a standard 52″ x 52″ square flange.

Aura Gravity Ventilators 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.

To install vents for air exhaust the Aura Gravity Vents should be placed on the upper portion (no more than 3 feet down from the peak) of the roof. Roof vents of this size can go on a (2/12 warm climate only) 3/12 to 5/12 pitched roof. For roofs that are pitched at 6/12 or steeper, please notify the sales department when ordering your roof vents. All Aura Vents can be modified so they can be installed on a 12/12 pitch roof.

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 42 inch Aura Gravity Ventilator, produces 2,538 cfm of air exhaust for attic ventilation.