This product has been discontinued.
Overview
Winter doldrums got you down? Or maybe you're depressed that your old furnace barely does the job while costing you an arm and a leg. Solve both problems with a Goodman GMH8 Series Two-Stage Gas Furnace. Built around a heavy-duty tubular heat exchanger and two-stage convertible gas valve, the GMH8 can deliver up to 80% AFUE performance with a low continuous fan speed for quieter air circulation, real warranty support, and multiple installation options.
Goodman delivers more than simple brand recognition with its superior products. This trusted and reliable company brings you some of the industry's top performing and economic products. Plus, Goodman products are made in the USA, and that includes the GMH18 gas furnace.
The 140k BTU 80% AFUE Multi Speed 2 Stage Goodman Gas Furnace - Upflow/Horizontal - 24.5" Cabinet is created with a heavy-duty steel shell painted with a powder paint finish to last. The heat exchanger is insulated to reduce the amount of heat lost from the unit for less than 2% air leakage. This combined with many of the other innovative features mean that you will keep more money in your pocket. Plus, this unit is known for its nearly noiseless sound level even when running at full capacity. For an added bonus, you can easily connect a humidifier to this unit. Simply connect that part to the low-voltage terminal on the easy-to-operate control board.
Goodman is so confident in this furnace that they provide each unit with serious, long term parts warranty protection. To extend that protection further, go online after purchase and register your unit within 60 days of installation. If you are unable to do so, call us and we will help.

Manufacturer Highlights
The Goodman® brand GMH Gas Furnaces offer energy efficiencies and operating sound levels that are among the best in the heating and cooling industry. Quality manufacturing as well as easy installation and maintenance make this unit one of the best values on the market.
Standard Features
- Dual-diameter tubular heat exchanger
- Two-stage gas valve convertible technology allows installer to activate the two-stage valve with the flip of a dipswitch
- 110V Silicon Nitride igniter designed for long igniter life
- Furnace control board with self-diagnostics, colorcoded low-voltage terminals, and provisions for electronic air cleaner and 24-volt humidifiers
- Control board stores the last five diagnostic codes in memory; simple push-button activation outputs the fault history to a flashing red LED
- Low constant fan allows homeowner to activate the low heat speed to efficiently circulate air throughout the home
- Self-adjusting feature automatically adjusts to high- or low-stage operation based on outside temperature without an outdoor temperature sensor
- Dual-certified for sealed combustion direct vent (2-pipe) or non-direct vent (1-pipe) applications
- All models comply with California NOx emissions standards
Cabinet Features
- Fully insulated, heavy-gauge steel cabinet with durable baked-enamel finish
- Foil-faced insulation lines the heat exchanger
- Designed for multi-position installation
- Easy-to-install top venting is standard; alternate flue/vent located on the right
- Airtight solid bottom for side-return applications and easy-cut tabs for effortless removal in bottom air inlet applications
- Convenient left or right connection for gas and electric service
- Coil and furnace fit flush for most installations
Warranty Terms
For a full description of all warranties applicable to this product as well as individual manufacturer requirements, please review the manufacturer's consumer brochure and/or product warranty documents. Online warranty registration must be completed within 60 days of installation. Due to state laws, online registration is not required in California or Quebec. Call for warranty availability on scratch & dent and surplus items.
Installation of any product must comply with all applicable codes and regulations. The service of a certified and trained electrical technician may be required for the installation process.
Specifications
Model | GMH81405DN |
---|---|
UPC | 663051454439 |
AHRI Number | 201696703 |
Gas Furnace Efficiency | 80% |
Air Flow Direction | Horizontal, Upflow |
Configuration | Floor Mounted |
Avg Coverage Area | 2,500 - 3,000 Sq Ft |
Blower Motor | Multi Speed |
Cooling Compatibility (up to) | 5 Ton |
Electrical Phase | 1-Phase |
Exhaust Pipe | Metal |
Fuel Source | Natural Gas |
Gas Valve | Two Stage |
Max Overcurrent Protection | 15 amps |
Primary Heating Capacity | 135,001 - 140,000 BTU |
Product Height (in) | 33.375 |
Product Length (in) | 28 |
Product Width (in) | 24.5 |
System Application Type | Central Split Systems |
Vent Connection | 6 inches |
Voltage | 120 |
Warranty | 10 Year Parts, Lifetime Heat Exchanger, 10 Year Unit Replacement |
Weight (lbs) | 132.0000 |
California Residents | see Prop 65 WARNING |