- Heavy duty Million Air stainless-steel, tubular heat exchanger - Stainless-steel secondary heat exchanger - Self calibrating modulating gas valve operates on two stage or single-stage thermostats - ComfortNet Communicating System compatible - Up to 96% AFUE - Efficient and quiet variable speed ECM circulator motor gently ramps up or down according to heating or cooling demand - Durable SureStart 110 volt Silicon Nitride Igniter - Furnace control board with self-diagnostics and provisions for air cleaner and humidifier - Auto comfort mode for enhanced dehumidification - Humidification output terminals - Quiet two-speed induced draft blower - Multiple continuous fan speed options offer quiet air circulation - Cabinet air leakage (QLeak) = 2%