Abstract: A system for utilizing furnace waste stack pipe heat which comprises elongating the waste stack pipe so that it defines a substantially rectangular shape and, when a blower is used in conjunction with the furnace, so that it extends over the blower in order that air drawn into the blower is preheated, the system further including placing a cover or hood over the elongated waste stack pipe and a baffle plate thereunder, each in close proximity thereto, for forcing the currents of air to move in close proximity to the hot waste stack pipe to readily absorb the heat therefrom.