The Goodman GDS80403AN is a multispeed gas furnace. It uses an aluminizedsteel, dualdiameter tubular heat exchanger. It has foilfaced insulation lining the heat exchanger compartment itself and the coil and furnace fit flush in most installation placements. The multispeed direct drive blower motor of this unit works quietly to adjust to changing temperature demands.This Goodman gas furnace is a singlestage, multispeed, multiposition heater. It uses a reliable Norton hot surface miniigniter to maintain a comfortable temperature in the home. This Goodman gas furnace has a heating capacity of 40,000 BTU.This heater comes from the GDS8 line of Goodman gas furnaces. This collection of Goodman gas furnaces has up to 80 AFUE (annual fuel utilization efficiency) rating. Many standard furnaces feature 60 AFUE, which means that this system can contribute to significant energy savings.This multiposition Goodman gas heater should be installed in a dedicated downflow position. This model features a furnace control board with selfdiagnostics and lowvoltage terminal block.