Independent Review · Updated June 2026

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

High-efficiency dual-fuel system with variable-speed motor and strong cooling capacity

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
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// Bottom Line
This 5-ton Goodman system is ideal for homeowners upgrading older equipment or contractors installing in mixed-fuel areas where propane and natural gas flexibility matters. The 96% AFUE furnace and 16 SEER1 air conditioner deliver strong energy savings, particularly in moderate climates.

Review

The Goodman 3.5/5-ton horizontal system bridges practical heating and cooling needs for residential installations across diverse fuel environments. Combining a 120,000 BTU furnace with a 42,000 BTU cooling capacity, this unit operates on propane or natural gas while delivering ENERGY STAR certification. Online Supply positions this as a mid-market option for contractors and homeowners seeking dependable performance without premium pricing, backed by Goodman's established service network and documented reliability history.

Heating efficiency reaches 96% AFUE through a two-stage burner that modulates output based on demand, reducing cycling losses. The air conditioner's 16 SEER1 rating and R410A refrigerant compatibility exceed baseline efficiency standards, qualifying buyers for regional utility rebates. The variable-speed ECM blower automatically adjusts airflow between 0-2000 CFM, minimizing energy waste during partial-load operation while maintaining consistent comfort across 120-square-foot to 150-square-foot spaces.

Pros & Cons

Pros

  • 96% AFUE heating efficiency reduces winter fuel costs by 10-15% compared to 80% units
  • 16 SEER1 cooling rating exceeds ENERGY STAR requirements and qualifies for utility rebates
  • Variable-speed ECM blower motor adapts to load, improving comfort and reducing runtime energy use
  • Two-stage burner provides quiet operation at part-load and better temperature modulation
  • Dual-fuel capability (natural gas and propane) adds flexibility for diverse installation scenarios

Cons

  • 73 dB noise level is moderately loud, comparable to older equipment, not quieter than premium alternatives
  • Single-stage compressor means cooling runs at one fixed capacity rather than modulating efficiency
  • Specs show conflicting tonnage data (3.5 tons in title, 5 tons in specs), creating confusion on actual capacity

Who Should Buy

Best For

Homeowners in rural or propane-dependent areas who value dual-fuel capability and strong heating efficiency. Contractors seeking reliable, rebate-qualified equipment for residential retrofit projects where cost-effectiveness and two-stage comfort matter.

Consider Alternatives If

Buyers prioritizing quiet operation or those seeking advanced variable-capacity cooling, which requires two-stage compressors not found in this unit.

3.5 Ton 15 SEER 96% AFUE 120,000 BTU Goodman Gas F
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Installation

This horizontal A-coil configuration mounts in attics or crawlspaces with 50 feet of suction line insulation (0.5 inch thickness). Requires 115V single-phase power and 23.5 to 40-amp breaker sizing. PVC or plastic exhaust flue compatibility simplifies venting. Most installations take 4-6 hours for experienced technicians, assuming ducting already exists.

Warranty & Reliability

Goodman provides a lifetime warranty on the heat exchanger (major component protection) and 10-year parts coverage with online registration. This strong heat exchanger guarantee reflects confidence in build quality, though registration is mandatory to activate it. Typical labor remains customer responsibility, which is standard in the market.

Specifications

SKULS381183850
Brand/ManufacturerOnline Supply
Cooling BTU42,000
Heating BTU120,000
RefrigerantR410A or R22
Electrical115 V. 1 Phase 60 Hz
WarrantyLifetime Heat Exchanger and 10 Years Parts with Online Registration
Decibel Level (dBA)73
Weight (in lbs)48.000000
FeatureSpec
Energy StarYes
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
Height34.5"
Width24.5"
Depth28.75"
ResourcesGoodman Brochure Goodman Install Instructions Goodman Parts Manual Goodman Service Manual Goodman Specifications Goodman Technical Information Goodman User Information Goodman 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.
ConfigurationUpflow/Horizontal
Liquid Line3/8"
Suction Line1 1/8"
StyleA-Coil
AHRI Certificate Number7368842
Airflow DirectionUpflow/Horizontal
Exhaust Flue RequirementPlastic / PVC
Product FeaturesRebate Available
Furnace Efficiency / AFUE96%
Blower MotorVariable Speed - ECM
Maximum CFM2000
Burner StagesTwo
Fuel TypePropane, Natural Gas
Suction Line Insulation Thickness1/2"
Length50 feet

Frequently Asked Questions

What's the difference between the 3.5-ton and 5-ton ratings listed? +
The specs sheet lists 5-ton tonnage with 42,000 BTU cooling capacity, which aligns with approximately 3.5-3.75 tons. This discrepancy suggests either a data entry error or the product title reflects a different configuration. Verify the AHRI certificate 7368842 with your distributor before ordering.
Can this handle both natural gas and propane without modifications? +
Yes, the unit supports both fuels, but it must be configured for one at installation. Conversion requires factory-authorized service and orifice changes. Plan fuel type selection before shipment to avoid costly field modifications.
How much will this reduce my energy bills compared to my 20-year-old system? +
Heating savings typically reach 30-35% over 80% AFUE units; cooling saves 20-25% versus 13 SEER systems. Exact gains depend on climate, usage patterns, and ductwork quality. Southern climates see larger cooling savings, northern regions benefit more from furnace efficiency.
Is 73 dB noise level acceptable for a bedroom attic installation? +
73 dB equals busy traffic volume. Bedroom installations benefit from sound damping or placement away from occupied rooms. Premium Goodman models offer quieter compressors, though this single-stage unit is typical for this price range.
What does online registration actually require for the lifetime heat exchanger warranty? +
Registration typically involves providing proof of purchase, installation date, and system serial number through Goodman's portal. Keep all paperwork. Failure to register within the specified timeframe voids the extended protection, so complete this immediately after installation.

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