Independent Review · Updated June 2026

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

Solid mid-tier efficiency system ideal for budget-conscious homeowners seeking reliable heating and cooling

8.2
IndustrialRank Score
Efficiency
8.5
Reliability
7.8
Value
8.0
Installation
8.5
Warranty
8.0
3.5 Ton 14 SEER 80% AFUE 100,000 BTU Goodman Gas Furnace and Air Conditioner System - Upflow
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// Bottom Line
This 3.5 ton Goodman system delivers 14 SEER cooling efficiency and 80% AFUE heating in a compact upflow configuration suitable for attics or utility closets. Best for homeowners prioritizing affordability without sacrificing reasonable efficiency ratings, or contractors building cost-effective replacement solutions for older systems.

Review

The Goodman 3.5 ton gas furnace and air conditioner system sits squarely in the mainstream market, offering proven reliability with respectable efficiency credentials. Manufactured by Goodman and distributed through Online Supply, this upflow-configured unit combines a 100,000 BTU furnace with 42,000 BTU cooling capacity in a single package. The 14 SEER rating and 80% AFUE efficiency reflect current industry standards rather than premium performance, making it attractive to contractors and homeowners balancing capability with cost constraints.

Performance specs reveal a competent workhorse rather than a efficiency champion. The system delivers 42,000 BTU of cooling capacity with a single-stage scroll compressor using R410A refrigerant. Two-stage burner operation and variable-speed blower motor reaching 2,000 CFM maximum provide adaptive comfort, adjusting output based on demand. The 80% AFUE heating efficiency is respectable but trails modern condensing furnaces. Electrical requirements remain modest at 120V single-phase with 22 to 35 amp breaker sizing, simplifying installation in standard residential panels.

Pros & Cons

Pros

  • 14 SEER cooling efficiency provides solid energy savings compared to older systems, reducing cooling costs by 20-30% versus 10 SEER units
  • Two-stage burner and variable-speed blower motor deliver comfort and efficiency gains, cycling down during moderate weather to reduce runtime
  • 80% AFUE meets modern heating standards with dual fuel capability supporting both natural gas and propane
  • Compact A-coil design fits tight attic spaces, measuring 34.5 inches tall with 21-inch width
  • 10-year warranty with online registration provides meaningful coverage for residential applications

Cons

  • 80% AFUE is not high-efficiency, mid-tier at best, missing out on 95%+ AFUE available in modern alternatives
  • Single-stage condenser limits ability to modulate cooling capacity, running at full output even during mild weather
  • 73 dB noise level ranks moderately loud, potentially noticeable in quiet neighborhoods or near bedrooms

Who Should Buy

Best For

Budget-conscious homeowners replacing systems in attics or utility closets who want a reliable, mid-efficiency solution without premium pricing. Contractors seeking dependable equipment for rental properties or client budgets under $5,000 will appreciate the balance of capability and cost.

Consider Alternatives If

Buyers in high-heat climates or those seeking maximum long-term energy savings should look at 16+ SEER systems with variable-capacity compressors, or homeowners prioritizing whisper-quiet operation may find the 73 dB level distracting.

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

Upflow A-coil configuration fits standard attic or utility closet installations with overall dimensions of 34.5 inches height, 21 inches width, and 28.75 inches depth. Liquid and suction lines measure 3/8 inch and 7/8 inch respectively, with pre-insulated suction line at 3/8 inch thickness. Metal flue exhausting is required. Variable-speed blower motor and two-stage gas operation require modern thermostats. Professional HVAC installation is strongly recommended for refrigerant charging and safety compliance.

Warranty & Reliability

Goodman provides 10-year parts warranty when registered online, covering compressor and major components. Registration is straightforward and extends protection beyond basic coverage. This warranty is typical for mid-tier systems but does not include labor costs. Extended warranty options may be available through distributors, and many contractors offer service plans bundled with installation.

Specifications

SKULS38783830
Brand/ManufacturerOnline Supply
Cooling BTU42,000
Heating BTU100,000
RefrigerantR410A
Electrical120 V. 1 Phase 60 Hz
Warranty10 Years with Online Registration
Decibel Level (dBA)73
Weight (in lbs)30.000000
FeatureSpec
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
Tonnage5 Ton
Height34.5"
Width21"
Depth28.75"
ResourcesGoodman Brochure Goodman Installation Instructions Goodman Parts Manual Goodman Service Manual 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 Line7/8"
StyleA-Coil
Airflow DirectionUpflow/Horizontal
Exhaust Flue RequirementMetal
Furnace Efficiency / AFUE80%
Blower MotorVariable Speed
Maximum CFM2000
Burner StagesTwo
Fuel TypePropane, Natural Gas
Suction Line Insulation Thickness3/8"
Length30 feet

Frequently Asked Questions

How does the 14 SEER rating compare to other systems? +
14 SEER represents solid mid-tier efficiency, roughly 40% more efficient than older 10 SEER units. It trails high-efficiency 16-18 SEER systems but costs significantly less. For moderate climates or budget-conscious buyers, 14 SEER delivers meaningful energy savings without premium pricing.
Is this system suitable for my attic installation? +
Yes, the upflow A-coil configuration and compact 34.5-inch height make it well-suited for attics. The variable-speed blower and two-stage operation minimize temperature swings. Ensure adequate clearance around the unit for airflow and maintenance access.
What's the difference between 80% AFUE and higher-efficiency furnaces? +
80% AFUE means 20% of fuel energy exits through the flue as waste. Modern 95%+ AFUE condensing furnaces capture that heat, reducing heating costs by 15-20% annually. The tradeoff is higher upfront cost. For mild climates, 80% AFUE remains cost-effective.
Can I use propane instead of natural gas? +
Yes, this system supports both fuels. Propane conversion requires a kit and recalibration by a licensed technician. If converting from natural gas, ensure your propane supplier handles residential delivery and your home has adequate storage capacity.
Does the 10-year warranty cover labor and refrigerant? +
The warranty covers parts only, not labor. Refrigerant is typically covered only if a manufacturer defect caused the loss. Registration is required. Review Goodman's warranty document carefully, and ask your installer about extended service agreements.

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