The Goodman GMH81205DN is a multi-position, multi-speed gas furnace that works on natural gas and gives an AFUE rating of 80%. This gas furnace features the patented aluminized-steel heat exchanger and durable Silicon Nitride Hot Surface Ignition System and the cabinet is heavy gauge, reinforced, insulated steel with baked enamel finish that provides extra durability and enables the user to install it in a variety of locations. The four speed direct-drive circulator bower motor provides quiet and energy efficient operation and the self adjusting feature of this Goodman GMH81205DN Upflow Furnace adjusts the level of the furnace to high or low according to the temperature conditions outside. The Patented TuffTubeTM dual-diameter tubular heat exchanger comes with a lifetime limited parts warranty and the furnace comes with a 10-year replacement warranty.