When ever its windy I can hear the bathroom vent flap opening and closing.
This is an obvious heat loss. I suppose all fans are prone to this. But I
have a roof flap, an extra in line damper used for dryers and a Panasonic
fan with a nearly useless flap. The pipe from the ventilator to the roof is
only about 2.5 feet in length. I can't figure what to do to stop it other
than removing the fan or replacing the ventilator. I have a window, so I
don't need a fan. What can I do other than finding a "better" ventilator?