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AV-04-C02 | Aura Vent 4″ Diameter 2″ Collar

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SKU: AV-04-C02 Category:

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

Click to enlarge pdf below for print

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:

4 in.
10.2 cm.

Outside Diameter:

7 in.
17.8 cm.

Square Flange (side length):

10 in.
25.4 cm.

Height of Head:

6 in.
15.2 cm.

Collar Height:

2 in.
5.1 cm.

Height of Flange:

0 in.
0 cm.

Total Height with Collar and Flange:

8 in.
20.3 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):

4 in.
10.2 cm.

Louver Height (outside):

4 in.
10.2 cm.

Size of opening btwn blades (inside):

0.125 in.
0.3175 cm.

Size of opening btwn blades (outside):

0.25 in.
0.635 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:

3/12 - 14°

Maximum Pitch Capacity (Standard Vent):

4/12 - 18.4°

Maximum Pitch Capacity (Modified):

12/12 - 45°

Free Air Space:

12.6 sq. in.
81.1 sq. cm.

Free Air Space:

0.0873 sq. ft.
0.0081 sq. m.

1:150 Ventilation Rule:

26.18 sq. ft.
2.432 sq. m.

1:300 Ventilation Rule:

52.36 sq. ft.
4.864 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:

26 CFM
Airflow in 6.4 KPH Wind: 0.74 CMM

5.2 MPH Wind:

38 CFM
Airflow in 8.4 KPH Wind: 1.08 CMM

7.4 MPH Wind:

51 CFM
Airflow in 11.9 KPH Wind: 1.44 CMM

9.8 MPH Wind:

59 CFM
Airflow in 15.8 KPH Wind8: 1.67 CMM

11 MPH Wind:

62 CFM
Airflow in 17.7 KPH Wind8: 1.76 CMM
Click to enlarge pdf for print

Our Aura Vents have UL Certification. Check out other details and specifics on
UL’s Online Certifications Directory.


This particular Aura Vent is 4 inches in diameter and has a 2 inch tall collar or neck (AV-04-C02) and has 12 inches of NFA.  If installed on the upper portion of the roof, this product can go on a 3/12 to 4/12 pitched roof. However, it can go up a 12/12 pitched roof with an undetectable modification. Please specify roof pitch when placing your order. All our 4 inch aluminum gravity ventilators come with a standard 10″ x 10″ square flange or base.

The Aura Vent works like a roof turbine but with no moving parts. This static vent relies on the Venturi Effect (the creation of an upward draft) when the wind blows.  Even the smallest breezes can create positive movement of air out of the vent. This movement of air is proportional to the wind speed, and can be measured in Cubic Feet per Minute or in Cubic Meters per Minute. Wind speeds of 11 MPH for example, produce 62 cubic feet of air per minute of attic ventilation.

Aura Vents are UL Listed and rated up to 50+ PSF or wind pressure above 200 MPH.  Certified by Texas Department of Insurance, Florida State & California Wild Fire approved. Aura Vents are constructed entirely out of aluminum so therefore they will never rust but come with a 5 year warranty.