Gravity Exhaust Shutters
Gravity exhaust shutters are used to keep air flow from blowing back into your exhaust fan when the unit is turned off. This helps with unwanted outside air entering your space. Another use is a passive solution to allow air out of your space when using a supply fan. They also keep water out when closed, and are available with optional bird and bug screens. They can be installed directly on a building wall, and are also able to be directly mounted onto some fan housings.