Independent Review · Updated June 2026

3.5 Ton 14 SEER 80% AFUE 100,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow

Solid mid-tier gas furnace and AC combo for budget-conscious contractors

7.8
IndustrialRank Score
Efficiency
7.5
Reliability
8.0
Value
8.2
Installation
8.5
Warranty
7.5
3.5 Ton 14 SEER 80% AFUE 100,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow
Current Price
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// Bottom Line
This 3.5-ton system works well for residential properties where upfront cost matters more than premium efficiency. The 80% AFUE furnace and 14 SEER cooling unit deliver respectable performance without the premium price tag of higher-tier equipment.

Review

Goodman's 3.5-ton gas furnace and AC combo represents the practical middle ground in residential HVAC systems. This downflow configuration paired with a 100,000 BTU furnace and 42,000 BTU air conditioner handles typical three to four-bedroom homes effectively. It's the kind of equipment contractors reach for when budget is the primary driver, yet basic performance standards still need meeting.

The 80% AFUE heating efficiency and 14 SEER cooling rating deliver adequate performance for moderate climates and average usage patterns. The two-stage gas burner modulates output for more consistent comfort than single-stage designs, while the multi-speed blower motor can ramp CFM from lower speeds up to 2000 maximum. However, these specs trail modern 95% AFUE furnaces and 16+ SEER systems by meaningful margins in energy consumption and long-term operating costs.

Pros & Cons

Pros

  • Two-stage burner provides flexible heating and better comfort than single-stage alternatives
  • 14 SEER cooling efficiency balances performance with affordability for most climates
  • Multi-speed blower motor allows customized airflow and quieter operation than fixed-speed units
  • Downflow configuration fits tight installations where upflow isn't possible
  • 10-year warranty with online registration offers decent coverage for the price point

Cons

  • 80% AFUE furnace is outdated by modern standards, missing out on 90%+ AFUE incentives and long-term energy savings
  • 14 SEER1 rating doesn't qualify for Energy Star certification, limiting appeal to efficiency-focused homeowners
  • 73 dB noise level runs louder than high-efficiency competitors, noticeable during operation

Who Should Buy

Best For

Budget-conscious homeowners and contractors installing systems in rental properties or homes where occupancy may be temporary. This unit makes sense for replacements in moderate climates where maximum efficiency ROI doesn't justify premium pricing.

Consider Alternatives If

Anyone prioritizing long-term energy savings, living in cold climates requiring high furnace efficiency, or seeking Energy Star certification for incentives or resale value.

3.5 Ton 14 SEER 80% AFUE 100,000 BTU Goodman Gas F
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Installation

Standard downflow installation fits most basement and utility closet applications. The 32.5-inch height, 29-inch width and depth require typical ductwork connections. Requires 208/230V single-phase 60 Hz power with 22 to 35 amp breaker sizing. Metal exhaust flue is mandatory. Scroll compressor design offers reliable field performance and straightforward service.

Warranty & Reliability

Ten-year coverage on parts and compressor with online registration provides reasonable protection against manufacturer defects. This is standard for mid-tier units but shorter than premium brands offering 12-year or lifetime compressor warranties. Registration is required, so document carefully at installation.

Specifications

SKULS38783830
Brand/ManufacturerOnline Supply
Cooling BTU42,000
Heating BTU100,000
RefrigerantR410A
Electrical208 / 230 V. 1 Phase 60 Hz
Warranty10 Years with Online Registration
Decibel Level (dBA)73
Weight (in lbs)30.000000
FeatureSpec
Exhaust Flue RequirementMetal
Furnace Efficiency / AFUE80%
Blower MotorMulti-Speed
Maximum CFM2000
ConfigurationUpflow / Downflow
Burner StagesTwo
Fuel TypeGas
Height32.5"
Width29"
Depth29"
ResourcesGoodman Installation Manual Goodman Specifications Goodman Brochure Goodman Warranty Information Goodman Service Instructions Goodman Kit Instructions Goodman Parts Manual 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.
Liquid Line3/8"
Suction Line7/8"
Tonnage3.5 Ton
StyleA-Coil
Energy StarNo
SEER1 (Efficiency)14
Condenser StagesSingle Stage
Compressor TypeScroll
Liquid Valve Size3/8"
Suction Valve Size7/8"
Max Breaker Size35 amps
Min. Breaker Size22 amps
Suction Line Insulation Thickness3/8"
Length30 feet

Frequently Asked Questions

Is this system Energy Star certified? +
No. The 80% AFUE furnace and 14 SEER cooling unit fall below Energy Star thresholds. Energy Star requires 95%+ AFUE furnaces and 16+ SEER cooling systems, meaning this unit won't qualify for many utility rebates or tax incentives.
What's the difference between upflow and downflow configuration? +
Downflow discharges conditioned air toward the floor, routing through ducts below the unit. This suits basements or utility closets where upflow space is limited. Upflow sends air upward, better for attic ducting. This model accommodates both, offering installation flexibility.
How does 14 SEER compare to newer cooling efficiency standards? +
14 SEER is respectable but mid-range. Modern units hit 16 to 22 SEER. In moderate climates, 14 SEER works fine, but hot or humid regions see meaningful energy waste versus high-efficiency alternatives. SEER1 ratings replaced old SEER in 2023, so direct comparisons with newer equipment require caution.
Is 80% AFUE furnace efficiency acceptable? +
Acceptable, not optimal. 80% AFUE is standard for lower-cost systems but trails 90-98% AFUE models by $800-2000 upfront and roughly 10-18% annual fuel savings. Cold climates especially benefit from higher AFUE. This makes sense primarily for budget retrofits.
Does registration requirement for warranty protection matter? +
Yes, absolutely. Goodman voids warranty without proof of online registration. Keep documentation and register immediately after installation to avoid coverage gaps during the ten-year period.

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