Goodman 80% 40,000 BTU Two Stage Low NOx Gas Furnace | 14" Width | Downflow / Horizontal

Goodman 40,000 BTU 80% AFUE Downflow/Horizontal Gas Furnace

Two-Stage Gas Heating with Enhanced Comfort

When winter temperatures arrive, this Goodman gas furnace delivers dependable whole-home heating with practical efficiency and durable performance. Designed with modern blower and reliable gas burner technology, as well as installation options for compatible applications, it provides a strong heating solution for residential use.

Key Benefits

• 40,000 BTU Heating Capacity – Perfect for 600–1,000 sq. ft. homes in various climates when properly sized and installed.
• 80% AFUE Efficiency – Converts approximately 80% of fuel consumed into usable heat for your home.
• 9-Speed ECM Blower Motor – Uses less electricity than older PSC motors while supporting improved airflow and circulation.
• Downflow/Horizontal Installation – Designed for downflow/horizontal applications to fit compatible installation layouts.
• 14" Cabinet Width – Designed to fit evaporator coils of a matching width.
• Two-Stage Gas Heating – Uses staged heating operation to support improved comfort compared to basic single-stage equipment.
• Convertible to Liquid Propane – Can be field-converted to use liquid propane with an optional conversion kit.
• Quiet, Durable Operation – Heavy-gauge steel cabinet and insulated design help reduce sound while protecting internal components.
• Strong Warranty Coverage – Backed by Goodman limited warranty coverage when properly installed and registered online.

Heating Capacity and AFUE Guidance

This furnace is perfect for 600–1,000 sq. ft. homes in various climates when properly sized and installed. With a 40,000 BTU input rating and 80% AFUE efficiency, it is designed to provide dependable heating for compatible residential applications. Proper furnace sizing should always be confirmed through a professional load calculation based on climate, insulation, windows, ceiling height, layout, air leakage, and other home-specific factors.

Efficient Everyday Heating Performance

An 80% AFUE furnace provides dependable gas heating performance for compatible residential applications. For example, a 40,000 BTU input rating at 80% AFUE provides approximately 32,000 BTUs of usable heating output, while the remaining heat is lost to the combustion process and exits through the venting. Because this is an 80% AFUE furnace, it requires metal flue venting. Homes with plastic or PVC furnace venting require a 90% AFUE or higher furnace. This furnace is designed for enhanced comfort control compared to basic single-stage equipment.

Advanced Airflow with a 9-Speed ECM Blower

The integrated 9-speed ECM blower motor provides improved electrical efficiency compared to older PSC blower designs. This blower helps support consistent air circulation throughout the home while reducing electrical consumption during operation.

Built for Long-Term Reliability

A heavy-gauge steel cabinet, durable hot surface igniter, self-diagnostic control board, and Goodman’s proven heat exchanger design work together to support long-term performance. The self-diagnostic controls simplify troubleshooting and service, while the insulated cabinet helps reduce operating noise.

Warranty

When installed according to applicable codes and registered online with Goodman, this furnace includes:

• 10-Year Parts Limited Warranty
• 10-Year Unit Replacement Limited Warranty
• Lifetime Heat Exchanger Limited Warranty

Warranty coverage requires proper installation and online registration. Installation by a qualified HVAC professional is recommended to maintain warranty eligibility.

What’s Included

• Goodman gas furnace

Recommended Accessories

• Wall-Mounted Thermostat – Provides compatible temperature control for the furnace and connected HVAC system.
• Propane Conversion Kit – Converts the furnace from natural gas to liquid propane when propane operation is required.
• Return Air Package – Provides return air components for a cleaner installation setup.
• Supply Plenum – Creates a proper supply air transition above the furnace.

Requirements, Considerations & Required Notices

• Professional Installation Required – This gas furnace should be installed and serviced by a trained HVAC technician in accordance with local codes and manufacturer requirements.
• Metal Flue Venting Required – This 80% AFUE furnace requires metal venting materials. Homes with plastic or PVC furnace venting require a 90% AFUE or higher furnace.
• Electrical Requirements – Requires 115-volt, single-phase power and proper circuit protection.
• Cabinet Width – Confirm the 14" cabinet width fits the available installation space and matched indoor equipment.
• Fuel Compatibility – Ships configured for natural gas operation. Liquid propane conversion requires the appropriate optional conversion kit.
• Installation Configuration – Designed for downflow/horizontal installations when installed according to manufacturer guidelines.

Low NOx Compliant

In California, many counties have a lower NOx emission requirement than the rest of the United States. The GD9T800403AX Goodman gas furnace is California Low NOx compliant. With a built-in low emission filter, this Goodman gas furnace produces less nitrogen oxides to be released into the atmosphere, lowering the overall amount of toxic greenhouse gases output of the average California home.

This furnace cannot be installed in Colorado or the following counties in California: Fresno, San Joaquin, Kern, Kings, Los Angeles, Madera, Merced, Orange, Riverside, San Bernardino, Stanislaus, Yolo, and Tulare. In these areas you are required to purchase an Ultra-Low NOx furnace. If you have any questions, please contact us.