This 4 inch Round Back Static Vent with Curb Mount Flange is 4 inches in diameter with a 2 inch tall collar. In other words, this vent has 2 inches of clearance between the base and the inner louvers. The model RBV-4-C2-CMF has 12 inches of net free area (NFA).
This Static Vent removes hot air in the summer and moisture from the attic in the winter for year-round ventilation. Because of the curb mount flange, this vent is for installation on top of a roof curb. In other words, this flange will only fit over roof curbs or an existing base of the same diameter. This allows for easy access to the attic or duct below.
To determine the number of vents you may need, see our Vent Calculator.
This static vent is ideal for venting out bathroom fans or range hoods. In addition, the round design is aerodynamic to withstand wind speeds up to 200 mph. The 6 inch Round Back Vent is great for residential roof applications because of its low profile. It can also be painted to match the color of the asphalt shingles.
AVP's Round Back Vents have the power to withstand hurricane-force winds. See some of our customer feedback. However, if you are looking to ventilate a duct, please see our Round Back Roof Jack for vents with a tailpipe adapter. On the other hand, AVP also offers Static Vents with flat flanges to be installed on roofs with a pitch of 3/12 or greater.