A metal furnace header gate system haying a recirculation port in the furnace, a hot gas generator, a gas blower, and a furnace door. The door has an embedded gas manifold and outlet ports that each connect the manifold to a directional nozzle. The blower draws exhaust from the recirculation port into the hot gas generator, which generates additional exhaust and mixes the exhaust gases together. The blower forces this exhaust mixture into the manifold, through the nozzles, and into the furnace. A computer controls the blower and the hot gas generator to regulate the system.