The 18 inch Aura Attic Fan is 18 inches in diameter and has an 8 inch tall collar. The model number is AF-18-C8 and exhausts air out at 2,200 CFM. All 18 inch gravity fans come with a standard 24″ x 24″ square flange.
A collar height of 8 inches is typically for low slope or flat roof ventilation. However, if installed on the upper portion of the roof, this attic fan can go on a 0/12 to 5/12 pitch roof in climate zones 1-6.
18 inch diameter attic fans are commercial size, therefore, should be in commercial settings. For those looking to ventilate their homes, please view attic fans with a smaller diameter.
The 18 inch Aura Gravity Fan exhausts air continuously even when the motor is off. This attic fan works passively because of the Venturi Effect. When the wind blows against the outer louvers this creates an upward draft which allows air to freely flow out.
This Attic Fan is also available with an optional Shut-Off Switch, Thermostat, and Humidistat (THSOS).
With 1/2 horsepower and 2,200 CFM, this 18 inch attic fan is perfect for ventilating attic spaces or plenums.
The 18 inch attic fan will remove heat from the attic during the summer. In addition, it will also remove moisture during the winter.
This movement of air is proportional to the wind speed and is measured in cubic feet per minute (CFM). Therefore, wind speeds of 11 mph for an 18 inch attic fan produces 634 CFM of air exhaust for attic ventilation.