Exhaust vent flap Why is my bathroom vent making noise? Most of the time the vent housing is simply full of dirt and dust. The exhaust flapper valve is a crucial component of the exhaust system that helps optimize engine performance and sound. The exhaust usually goes across from the air vent to help pull the fresh air through the bathroom. To prevent dryer dampers from flapping, install a vent hood, apply stoppers, adjust the spring load, add weights to the flaps, or replace the damper. 76"D x 7. How To Fix a Noisy Range Hood The damper (flap) of the vent may also be loose or missing, allowing water to enter. Also see https: 【GREAT FOR HOME USE】The flap in dryer vent cover is sealed from one side to prevent air entering the ventilation system. It doesn't seem like the flap(s) shutting by gravity would make that much noise. Grease from a range hood or lint from a clothes dryer can jam the flap open. Just in case, I installed a backdraft damper in line between the exhaust fan and this vent hood. pbtiwsbrxflvbjvzwgwgkypdtyxvlouxdgeetiybosbenrcsqmqrdierlsnqpwcvflbqkbgknvlmxe