Independent Review · Updated June 2026

3.5 Ton 16 SEER 96% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow

High-efficiency dual-fuel system with 16 SEER cooling and 96% AFUE heating for $3,136

8.2
IndustrialRank Score
Efficiency
8.5
Reliability
7.8
Value
8.0
Installation
8.5
Warranty
8.0
3.5 Ton 16 SEER 96% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow
Current Price
$3136
Check Price at HVACDirect → Shop Now at HVACDirect
Authorized dealer · Full manufacturer warranty
// Bottom Line
This Goodman 3.5-ton system delivers solid efficiency ratings (16 SEER, 96% AFUE) at an aggressive price point, making it ideal for budget-conscious contractors and homeowners replacing older equipment. The downflow configuration and variable-speed ECM blower add flexibility for various installation scenarios.

Review

Goodman's 3.5-ton downflow system represents a mainstream option in the budget-to-mid-range HVAC market. At $3,136, this package combines a 120,000 BTU furnace with a 42,000 BTU air conditioner in a single assembly, targeting homeowners and contractors who prioritize upfront cost savings. The downflow configuration serves a specific installation niche, particularly in basements and crawlspaces where upflow equipment won't fit. Online Supply's distribution of this Goodman unit keeps pricing competitive while maintaining factory backing.

Performance specifications read impressively on paper. The 16 SEER rating places this unit in the high-efficiency category for air cooling, while the 96% AFUE furnace heating efficiency is among the best available for gas equipment. The variable-speed ECM blower motor adjusts airflow between 0 and 2,000 CFM based on demand, improving comfort and reducing energy waste compared to fixed-speed designs. Two-stage burner operation lets the furnace run at reduced capacity during partial-load conditions, further optimizing efficiency. R410A and R22 compatibility broadens installation flexibility for both new construction and retrofit scenarios.

Pros & Cons

Pros

  • 16 SEER cooling efficiency qualifies for ENERGY STAR with potential rebates, lowering net cost
  • 96% AFUE furnace heating efficiency is excellent for natural gas or propane systems
  • Variable-speed ECM blower motor provides better comfort and quieter operation than single-speed alternatives
  • Two-stage burner allows low-fire operation during mild weather, improving efficiency and reducing cycling
  • Scroll compressor technology is proven reliable with minimal maintenance requirements
  • Flexible refrigerant compatibility with R410A or R22 for retrofit applications

Cons

  • Tonnage mismatch in spec sheet shows 5-ton condenser paired with 3.5-ton rating, creating confusion and potential compatibility issues
  • 73 dB noise level is moderate to high, noticeable during AC operation in quiet residential settings
  • Single-stage compressor limits part-load efficiency compared to variable-capacity alternatives at higher price points
  • Requires 40-amp maximum breaker, adding electrical upgrade costs in older homes with limited panel capacity

Who Should Buy

Best For

Contractors performing equipment replacements on tight budgets and homeowners in moderate climates where a 3.5-ton capacity matches their cooling load. This system works well for downflow or horizontal installations in basements or crawlspaces with adequate space for the 30-inch height.

Consider Alternatives If

Buyers in extreme climates needing true variable-capacity compressors, sound-sensitive installations in open-concept homes, or anyone uncomfortable with the conflicting tonnage specifications in the product documentation.

3.5 Ton 16 SEER 96% AFUE 120,000 BTU Goodman Gas F
$3136
Buy at HVACDirect →

Installation

Installation requires standard HVAC practices with some caveats. The downflow orientation demands proper ducting below the unit and adequate clearance in the installation space. PVC exhaust piping is mandatory per spec, which simplifies venting compared to metal flue pipes. Electrical setup needs a 23.5 to 40-amp breaker at 115V, 1-phase, 60Hz. Refrigerant line sizing uses 3/8-inch liquid and 1 1/8-inch suction lines with 1/2-inch insulation, requiring precision during brazing.

Warranty & Reliability

The 10-year parts warranty with online registration is standard Goodman coverage and protects against compressor, component, and most mechanical failures. Registration is mandatory to activate full coverage, so buyers must complete this step immediately after purchase. This warranty provides moderate peace of mind but excludes labor costs, which vary by contractor. Extended protection plans are often available separately through the installer.

Specifications

SKULS381183850
Brand/ManufacturerOnline Supply
Cooling BTU42,000
Heating BTU120,000
RefrigerantR410A or R22
Electrical115 V. 1 Phase 60 Hz
Warranty10 Years 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
Height30"
Width24.5"
Depth21"
ResourcesCAPF Installation Manual CAPF 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.
AHRI Certificate Number7368845
Airflow DirectionDownflow/Horizontal
Exhaust Flue RequirementPlastic / PVC
Product FeaturesRebate Available
Furnace Efficiency / AFUE96%
Blower MotorVariable Speed - ECM
Maximum CFM2000
ConfigurationUpflow / Downflow
Burner StagesTwo
Fuel TypePropane, Natural Gas
Liquid Line3/8"
Suction Line1 1/8"
StyleA-Coil
Suction Line Insulation Thickness1/2"
Length50 feet

Frequently Asked Questions

Why does the spec sheet list both 3.5-ton and 5-ton ratings? +
This appears to be a documentation error from the distributor. The cooling capacity of 42,000 BTU confirms 3.5-ton sizing. Verify with Online Supply or the AHRI certificate (7368845) before purchase to ensure you receive the correct tonnage for your application.
Can this downflow unit work in an upflow installation? +
The spec lists 'Upflow/Downflow' configuration capability, suggesting flexibility, but downflow is the primary design. Consult the CAPF Installation Manual before attempting upflow conversion, as internal airflow paths may differ from traditional upflow coils.
How does 16 SEER compare to other 3.5-ton systems at this price? +
16 SEER is competitive in the $3,000-$3,500 range and qualifies for ENERGY STAR certification plus potential utility rebates. Some competitors offer 14-15 SEER at lower prices, but this unit's efficiency advantage recovers its higher cost within 3-5 years through lower energy bills.
Is the 73 dB noise level acceptable for residential use? +
73 dB is comparable to a garbage disposal, noticeable but tolerable in most homes. Sound-sensitive buyers or installations near bedrooms should consider units rated 68 dB or lower, typically available at 18+ SEER ratings and higher prices.
Does the warranty cover refrigerant and labor? +
The 10-year warranty covers parts including refrigerant but excludes labor installation and repair costs. Homeowners pay technician time separately, typically $100-$200 per service call in most markets.

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