Independent Review · Updated June 2026

3.5 Ton 15 SEER 96% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Horizontal

96% AFUE furnace with variable-speed blower, strong efficiency at accessible pricing

8.2
IndustrialRank Score
Efficiency
8.5
Reliability
7.8
Value
8.0
Installation
8.5
Warranty
8.0
3.5 Ton 15 SEER 96% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Horizontal
Current Price
$3136
Check Price at HVACDirect → Shop Now at HVACDirect
Authorized dealer · Full manufacturer warranty
// Bottom Line
This Goodman system delivers solid heating efficiency and ENERGY STAR certification at $3,136, making it attractive for contractors installing in tight crawlspaces or attics where horizontal configuration matters. Best suited for homeowners in moderate climates who prioritize efficiency gains over premium brand cachet.

Review

The Goodman 3.5-ton horizontal furnace and air conditioner system occupies a practical middle ground in the HVAC market. Priced at $3,136, it competes against budget models while incorporating efficiency features typically found in higher-end equipment. The horizontal configuration specifically addresses installer pain points, making it valuable for retrofit work in space-constrained environments. Online Supply backs this unit with ENERGY STAR certification and a 10-year warranty, signaling confidence in component durability.

Performance metrics tell a compelling efficiency story. The furnace achieves 96% AFUE using a two-stage burner that modulates heating output, reducing cycling losses. Cooling capacity rates at 42,000 BTU (3.5 tons nominal), though the spec sheet inconsistently lists 5-ton tonnage elsewhere. The variable-speed ECM blower motor runs at up to 2,000 CFM, automatically adjusting airflow to match heating and cooling loads. This approach cuts electricity consumption compared to single-speed alternatives. R410A refrigerant and scroll compressor technology provide reliable, efficient cooling delivery.

Pros & Cons

Pros

  • 96% AFUE furnace efficiency reduces fuel consumption and monthly heating costs noticeably
  • Variable-speed ECM blower motor adjusts to actual heating demand, improving comfort and reducing runtime
  • Horizontal configuration fits tight spaces where traditional upflow units won't fit
  • Two-stage burner and scroll compressor provide modulated heating and cooling
  • ENERGY STAR qualified with 10-year parts warranty upon registration
  • Accepts both natural gas and propane, offering fuel flexibility for rural installations

Cons

  • SEER rating shows 16 in specs but headline claims 15 SEER, creating labeling inconsistency
  • Single-stage condenser limits cooling modulation compared to two-stage alternatives
  • Goodman brand carries lower contractor reputation than Lennox or Carrier in some markets
  • 73 dB noise level runs moderately loud during operation

Who Should Buy

Best For

Contractors installing systems in attics, crawlspaces, or basements where horizontal orientation is mandatory, and homeowners seeking efficient gas furnaces without premium pricing. Works particularly well in climates with 40-60 heating degree days where furnace runtime justifies efficiency investment.

Consider Alternatives If

Homeowners prioritizing quiet operation should evaluate this 73 dB unit against quieter competitors, and buyers in very cold climates may find two-stage cooling insufficient for summer demands.

3.5 Ton 15 SEER 96% AFUE 120,000 BTU Goodman Gas F
$3136
Buy at HVACDirect →

Installation

Horizontal installation requires clear vertical height of 24.5 inches and adequate depth of 21.125 inches. PVC or plastic exhaust flue compatibility eliminates corrosion concerns with condensing furnaces. Electrical requirements demand 208/230V single-phase 60Hz service with 23.5 to 40 amp breaker sizing. Suction line insulation thickness of 1/2 inch and 50-foot liquid line length accommodate most residential layouts. Straightforward ductwork connections via standard ports.

Warranty & Reliability

Goodman provides a 10-year parts warranty upon online registration, a solid mid-tier coverage level. This covers furnace heat exchanger, compressor, and coil failures but typically excludes labor costs. Registration is mandatory to activate coverage, so documentation is critical. Compare this to competitors offering lifetime compressor warranties or extended coverage at additional cost.

Specifications

SKULS381183850
Brand/ManufacturerOnline Supply
Cooling BTU42,000
Heating BTU120,000
RefrigerantR410A or R22
Electrical208 / 230 V. 1 Phase 60 Hz
Warranty10 Years with Online Registration
Decibel Level (dBA)73
Weight (in lbs)48.000000
FeatureSpec
AHRI Certificate Number7368845
Airflow DirectionDownflow/Horizontal
Exhaust Flue RequirementPlastic / PVC
Product FeaturesRebate Available
Furnace Efficiency / AFUE96%
Blower MotorVariable Speed - ECM
Maximum CFM2000
ConfigurationHorizontal
Energy StarYes
Burner StagesTwo
Fuel TypePropane, Natural Gas
Height24.5"
Width26"
Depth21.125"
ResourcesCHPF Installation Manual CHPF Specifications Sheet Goodman Evaporator Coil Warranty You will need Adobe® Acrobat® Reader to view PDF documents.
Safety InformationPROPOSITION 65 WARNING This product and many products on our site may contain a chemical know to the state of California to cause cancer or birth defects or other reproductive harm. For more information about Proposition 65 please Click Here.
SEER1 (Efficiency)16
Condenser StagesSingle Stage
Compressor TypeScroll
Liquid Valve Size3/8"
Suction Valve Size7/8"
Max Breaker Size40 amps
Min. Breaker Size23.5 amps
Tonnage5 Ton
Liquid Line3/8"
Suction Line1 1/8"
StyleA-Coil
Suction Line Insulation Thickness1/2"
Length50 feet

Frequently Asked Questions

Does this unit qualify for utility rebates? +
Yes, the product listing notes rebates are available. ENERGY STAR certification makes it eligible for many utility incentive programs, though rebate amounts vary by region and utility provider. Contact your local utility or HVAC contractor for specific rebate eligibility and application requirements.
Can I install this in my attic given the space constraints? +
Possibly. Horizontal configuration requires 24.5 inches of vertical clearance and 21.125 inches depth. Measure your attic joists and available space carefully. The 48-pound weight is manageable for attic installation with proper supports and framing reinforcement for floor joists.
How does 96% AFUE compare to standard furnaces? +
Standard furnaces operate at 80-85% AFUE, meaning 96% AFUE recovers substantially more heat from fuel combustion. Over 15 years, this 11-16 point efficiency gain translates to approximately 10-20% lower heating bills depending on usage and local gas rates.
What's the difference between the claimed 15 SEER and the 16 SEER in the specs? +
This appears to be a documentation error or rating inconsistency. Verify the actual SEER rating with the AHRI certificate number 7368845 directly on the AHRI database before purchase. The difference matters for rebate eligibility and cooling cost projections.
Is the 10-year warranty transferable if I sell my home? +
Goodman warranties typically transfer to subsequent owners with proper registration documentation. Confirm transfer terms with Goodman customer service before purchase, as some coverage limitations may apply to second owners.

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