We're preparing to upgrade our kitchen and install a better range hood - and have a question regarding the damper located in the vent. Are dampers available that are designed to help keep frigid cold air from coming down the vent during the Winter season? Our existing vent has the thin metal damper that doesn't stop much cold air.
There are usually two of these dampers in the line. One out of the fan itself and the other at the exhaust point. One way to cut down on the draft is to make sure the ducts are insulated if they pass through unheated attic, crawlspaces and the like.