Our clothes dryer vent has a recommended outside louvered cover, the type with 4 horizontal flaps. The louvers are clear, close properly, and work well. The pipe from the dryer to the wall is only 6" long. The exterior cover is well caulked underneath, and the inside of the vent opening is well sealed.
In the winter (now!) the cold air still enters the dryer when it's not in use, and the cold radiates from the dryer sides and bottom. Is there anything I can do to stop the cold from entering? Other than installing an open/close "valve" on the vent, which is not feasible and would be dangerous, I can think of nothing.