The Aura Solar Fan uses both solar and wind to power the ventilator. It exhausts air continuously even when there is no sun and the motor is off. It works passively because of the Venturi Effect. When wind blows against the outer louvers this creates an upward draft which allows air to freely flow in and out of the vent.
The 1/8 inch louvers are designed to prevent rain, snow, insects and animals from entering inside the fan.
The Aura Solar Fan comes in an array of diameters and collar heights allowing for installation in any climate zone. See the Climate Zone Chart to determine the proper collar height for installation in your area.