The 59MN7B Multipoise Variable-Capacity Condensing Gas Furnace features the modulating Infinity® System. The innovative modulating gas valve is at the heart of this furnace’s quiet operation, along with the variable-speed Infinity ECM blower motor and variable-speed inducer motor. This furnace also provides 3.5 times tighter temperature control than single stage furnaces. With an Annual Fuel Utilization Efficiency (AFUE) up to 98.5%, this Infinity gas furnace provides exceptional savings over standard furnaces as well. This Infinity Gas Furnace also features 4-way multipoise installation flexibility. The 59MN7B can be vented as a direct vent/two-pipe furnace or as an optional ventilated combustion air application. A Carrier Infinity® Control and an Infinity® Air Conditioner or Heat Pump can be used to form a complete Infinity System. Low NOx units are designed for California installations and meet 40 ng/J NOx emissions. Can be installed in air quality management districts with a 40 ng/J NOx emissions requirement. All sizes are design certified in Canada. This furnace is not designed for use in recreation vehicles, manufactured (mobile) homes or outdoors.