The fan in my bathroom has a weighted flap that is supposed to prevent wind for blowing into the house when windy, but instead, it flaps loudly when the wind blows. It vents out the side of the house. It has a set of baffles there too, that are supposed to keep the wind from blowing inside, but those are not strong enough either. I also built a housing over the vents on the side of the house, so the wind could not hit the vent directly. Not of this has been enough to stop the wind from coming into the house. We have a flat roof, so there is no access to the fan from above.

I'm now thinking that I need to put something like a servo inside the fan that will hold the flap shut, and open when the fan is turned on. This sounds difficult, does anyone have a better solution for me? Are there any fans on the market that already have this functionality?

Thanks