A preheat charging system for preheating scrap metal prior to delivery to a melting furnace. The system includes a preheating station having a heating chamber adapted to receive scrap metal. Hot gas from a burner chamber is circulated around the scrap metal. The burner chamber is adapted to receive exhaust gas from a hot exhaust gas source such as a melting furnace. A burner apparatus is mounted within the burner chamber in a flow path of an exhaust inlet port. The burner is configured to supply supplemental heat on demand to the heating chamber to supplement the hot exhaust gas. A first fan can be provided to direct exhaust air from a furnace to the burner chamber. A second fan can be provided for directing air into the burner apparatus.