Would it make sense to somehow block off the pipe-chimney during times I do not use my stove to keep oil-burner warmed air from escaping up the chimney? (I've sealed up all the exhaust fans in the house in the baths and kitchen - no risk of too much humidity in winter). Attached is a photo of my stove showing the pipe that goes up and then bends to exhaust out the wall. This stove has no damper to close. I can slide the metal bar across the top front air holes to control air inflow from there (but assume it is not air tight as no gaskets). I understand that there is a secondary air intake from the back that lets air come in from the top into the stove to perform a secondary burn, and that is an area I cannot reach so assume it is always "open". Your thoughts?