What is the correct way to seal an unused exterior vent without replacing siding etc? This is an old, 4'' dryer vent. My current plan would be to first caulk around the flap to close any air gaps and then maybe use some spray foam and insulation?

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  • Sure. Sounds good. Except spray foam is insulation. No need for anything else.
    – isherwood
    Jun 21, 2022 at 13:27
  • Maybe ball up some old aluminum window screen and place inside the tube.
    – crip659
    Jun 21, 2022 at 14:46
  • I'd open the flap, stick some fiberglass insulation into the first 6 inches or so of the ductwork, and then seal the flap. That makes it really easy to undo some day in the future. Jun 21, 2022 at 17:08
  • The screen is in addition to other sealing/insulation efforts.
    – crip659
    Jun 21, 2022 at 17:09


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