Goodman Ultra-Low Nox Furnace California | 40000 BTU 80% Efficient Gas Furnace Multi-Speed ECM | Upflow / Horizontal | R32 (GR9S800403AU)
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Key features
- 40,000 BTU output rated for smaller homes and single-zone applications
- 80% AFUE efficiency meets California Ultra-Low NOx combustion standards
- Multi-speed ECM blower motor reduces electrical consumption versus PSC motors
- Upflow and horizontal installation configurations supported
- Single-stage heating operation with straightforward controls
- Compatible with R-32 refrigerant coil systems for split-system installations
About this system
The Goodman GR9S800403AU is a 40,000 BTU, 80% AFUE upflow/horizontal gas furnace built specifically to meet California’s strict Ultra-Low NOx emissions requirements. At 80% efficiency it falls into the baseline AFUE tier, meaning roughly 20 cents of every dollar in gas goes up the flue rather than into your home. That is a real trade-off compared to 96% condensing units, but it also means a simpler, single-stage heat exchanger, no secondary condensate drain, and a shorter, lower-cost installation in homes where a high-efficiency condensing furnace would require re-routing PVC drain lines.
The multi-speed ECM blower motor is the standout spec here. ECM motors consume significantly less electricity than standard PSC motors and allow the furnace to ramp airflow to match the actual demand of your duct system, which improves comfort, reduces cold spots, and helps the system work more efficiently with any air conditioning or heat pump it is paired with. The R-32 refrigerant designation in the model string refers to the paired coil or system compatibility rather than the furnace itself, since furnaces do not use refrigerant. This unit is sized for smaller homes or zone applications, typically up to around 1,000 to 1,400 square feet depending on insulation and climate zone. It is a practical, code-compliant choice for California homeowners replacing an aging furnace without upgrading the entire system.
The GR9S800403AU delivers a code-compliant, affordable furnace replacement for California homeowners who need Ultra-Low NOx compliance and do not require the fuel savings of a high-efficiency condensing unit. The ECM blower is a genuine comfort upgrade, but 80% AFUE means meaningfully higher annual gas costs than 96% alternatives, and Goodman's long-term reliability record warrants honest expectations. It earns its place as a value pick, not a premium one.
Overall score is the average of the five ratings above.
What we like
- Priced 15 to 25 percent below comparable Carrier, Trane, and Lennox models
- Meets California Ultra-Low NOx requirements out of the box
- ECM blower motor improves comfort and lowers fan electricity use
- Simpler 80% installation with no condensate drain lines required
- Widely available replacement parts and a large national installer network
Trade-offs
- 80% AFUE leaves roughly 20% of fuel cost as waste heat versus 95-96% alternatives
- Goodman's ConsumerAffairs score of about 2.5 out of 5 reflects real owner frustration with repair costs after year 7
- Dual-run capacitors are a documented recurring failure point, typically requiring a 300 to 600 dollar service call
- Single-stage operation means the furnace is always at full fire or off, which is less efficient and comfortable than modulating or two-stage units
What homeowners and pros say about Goodman
Homeowners who choose Goodman furnaces most often praise the upfront cost savings, and that sentiment shows up consistently in Google dealer reviews, where the brand averages around 3.8 out of 5 stars across hundreds of location-based ratings. Affordability is the single most repeated reason buyers chose Goodman over Carrier, Trane, or Lennox. HVAC technicians tend to offer a more measured view: they note that a Goodman installed carefully by an experienced contractor performs close to its specs, but that sloppy installations amplify the brand’s known weak points faster than they would with more forgiving premium equipment.
The documented failure modes are worth knowing before you buy. Dual-run capacitors are the most frequently reported repair on Goodman equipment, though at 300 to 600 dollars it is a manageable fix. Evaporator coil leaks appear in a meaningful share of owner reviews, and the ConsumerAffairs score of roughly 2.5 out of 5 reflects owners who ran into escalating repair costs after about year 7. That score comes from a complaint-skewed platform, so it overstates dissatisfaction relative to the broader install base, but the pattern is real enough to plan around. For this specific furnace, there is no compressor to worry about, which removes one of the documented Goodman failure modes entirely. What remains is a straightforward gas furnace that rewards a quality installation and honest maintenance expectations.
Sources: ConsumerAffairs Goodman owner reviews, AHRI Directory of Certified Product Performance, U.S. DOE appliance and equipment efficiency standards, Goodman product specification sheets.
How it compares
| Brand | Comparable model | SEER2 | Stage | Price position |
|---|---|---|---|---|
| Goodman | GR9S800403AU | N/A (furnace only) | Single-stage | Value pick |
| Carrier | Performance 80 (58TP) | N/A (furnace only) | Single-stage | Moderately higher than Goodman |
| Trane | S8X1 80% Single-Stage | N/A (furnace only) | Single-stage | Moderately higher than Goodman |
| Lennox | Merit ML180 | N/A (furnace only) | Single-stage | Higher than Goodman, lower than Lennox Elite series |
Competitor rows are comparable single-stage units at similar efficiency; price is relative position, not a quote.
Questions about this system
Is an 80% furnace still legal to install in California in 2024 and 2025?
In most California climate zones, 80% AFUE furnaces remain legal for replacement installations, but regulations vary by local jurisdiction and are tightening over time. Always confirm with your installer and local building department before purchasing, as some areas now require higher efficiency minimums or have electrification mandates for new construction.
What does the Ultra-Low NOx rating actually mean for this furnace?
California Air Resources Board regulations require residential gas furnaces sold in the state to produce no more than 14 nanograms of NOx per joule of heat output. This model meets that standard. It has no impact on efficiency or heating performance but is a hard legal requirement for sale and installation in California.
Why does this furnace list R-32 in the model number if furnaces don't use refrigerant?
The R-32 designation in the model string indicates this unit is matched and certified for use with R-32 refrigerant coils in a split cooling system, ensuring the furnace cabinet and coil are compatible. The furnace itself burns natural gas and does not contain or circulate any refrigerant.
How much can I expect to spend on repairs over the first 10 years based on Goodman's track record?
The most commonly reported repair is a failed dual-run capacitor, which typically runs 300 to 600 dollars including labor and is usually a one-time fix. Owner feedback on ConsumerAffairs shows repair costs becoming more frequent and frustrating after roughly year 7, so budgeting for at least one or two service calls beyond routine maintenance over a decade is reasonable.
Will the 40,000 BTU output be enough for my home, or should I size up?
At 80% AFUE, this unit delivers roughly 32,000 BTU of usable heat output. That is generally sufficient for well-insulated homes up to about 1,000 to 1,400 square feet in mild California climates, but the right answer depends on a Manual J load calculation. Oversizing causes short cycling, which increases wear and reduces comfort, so resist the instinct to go bigger without a proper calculation from your installer.
Specifications
| Furnace output | 40000 BTU |
| Configuration | Upflow |
| Refrigerant | R-32 |
| Model | GR9S800403AU |