Furnace was a Trane forced warm air manufactured in 1997. The furnace has a humidifier.
Return duct has a supply ventilation from the outdoors.
My question is in a cold climate like Cleveland is it really needed?
What advantages and disadvantages would this have. It does have a damper that can be closed or opened. There was no motorized damper.
Home is a 2 story colonial about 2500 sq. ft.