Up To 98% AFUE Communicating, Modulating Gas FurnaceFeatures: 98% AFUE, AllModels, All Positions All Models Have Earned The Energy Star Modulating Heating Operation (40% - 100% Capacity) Observer Communicating Control System Xtra SEER Variable Speed ECM Blower Motor Supports Single- and Two-Stage Cooling Units Dehumidification Feature In Cooling California Nox Approved Certified To Leak 2% or Less Of Nominal Air Conditioning CFM Delivered When Pressurized To 1' Water Column with All Present Air Inlets, Air Outlets, and Condensate Drain Port(S) Sealed Tougher Flame Roll-Out Sensors Standard Adjustable Heating Blower Off Delay Factory Set Blower On Delay Stainless Steel RPj Primary Heat Exchanger Stainless Steel Secondary Heat Exchanger High Temperature Limit Control Prevents Overheating Direct Ignition with Silicon Nitride Ignitor Quieter Operates Quieter At Lower Heating Rates Variable Speed Induced Draft Combustion Blower Variable Speed ECM Blower Motor Insulated Steel Cabinet Easier To Install and Service: Direct Vent (2-Pipe) or Ventilated Combustion Air 24 Vac Humidifier Terminal Electronic Air Cleaner Terminal 35' (889mm) High, For Ease Of Installation and Room For Service Innovative Knobs For Easy Door Removal and Secure Attachment Factory Shipped For Natural Gas, with Propane Gas Conversion Kits Available Four Position - Upflow/Downflow/Horizontal (Left/Right) Installation At Least Twelve Different Venting Configurations Through The Casing Flue Pipe For Counterflow or Horizontal Applications with Accessory Kit (order Separately) Concentric Vent Available Simple Troubleshooting Of Gas Valve Self-Configuring and Communicating Control Slide Out Heat Exchanger Assembly and Blower Assembly Warranty: * 10 Year No Hassle Replacement Limited Warranty Lifetime Heat Exchanger Limited Warranty with Timely Registration 5 Year Parts Limited Warranty - with Timely Registration, An Additional 5 Year Parts Limited Warranty * Applies To original Purchaser/Homeowner, Some Limitations May Apply. See Warranty Certificate For Complete Details.