vertically venting bathroom fan / damper / cold air

New construction house one floor:  The instructions state we can vent the Panasonic bath fan through the roof, (which is shortest route) but how do we stop the cold air… New construction house one floor:  The instructions state we can vent the Panasonic bath fan through the roof, (which is shortest route) but how do we stop the cold air…Read MoreGreenBuildingAdvisor