The 59MN7A Multipoise Variable-Capacity Condensing Gas Furnace features the Modulating Infinity™ System. The innovative modulating gas valve that can modulate up as well as modulate down is at the heart of this furnace’s extremely 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. A Carrier Infinity® Control and an Infinity Air Conditioner or Heat Pump can be used to form a complete Infinity System.