Abstract: A heat exchanging chimney in the form of a tubular heat exchanger which functions as a furnace and which is mounted above a conventional fireplace with a preferably transparent or translucent closure means over the front is described. The fireplace is constructed such that it draws outside air for combustion of the fuel and not air from the rooms being heated. The chimney is specifically in the form of at least one vertically oriented multiple tube shell type heat exchanger in place of the conventional fireplace chimney wherein the flue gases pass inside the tubes and the room air is heated inside the shell. In operation, the fireplace and heat exchanging chimney achieve substantial economies in utilization of fuel, particularly wood, over fireplaces with conventional chimneys.