There is a vent in the duct directly above my furnace. This is in the air out side, not the return duct.
Is there a reason I should have this duct open? It was open when I bought the house a few months ago, but this seems like a waste, heating and cooling the basement.
If there is a reason to have it open, should it be open only during certain seasons? (Open for heating, closed for cooling, etc..)
This is an Amana AMEH800805CX. (pictured below)