Independent Review · Updated June 2026

3.5 Ton 13 SEER 96% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow

High-efficiency 3.5-ton combo system with 96% AFUE and 13 SEER for budget-conscious upgrades.

7.9
IndustrialRank Score
Efficiency
8.4
Reliability
7.6
Value
8.1
Installation
8.2
Warranty
7.9
3.5 Ton 13 SEER 96% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow
Current Price
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// Bottom Line
This Goodman system delivers solid efficiency gains at an attractive price point for homeowners replacing aging equipment or contractors stocking standard residential units. It's particularly appealing for downflow installations in tight crawl spaces where configuration flexibility matters.

Review

The Goodman 3.5-ton gas furnace and air conditioner combo represents a straightforward approach to whole-home climate control. Positioned as an Online Supply house brand offering through independent distributors, this downflow-capable unit targets budget-aware contractors and homeowners seeking reliable performance without premium pricing. With 120,000 BTU heating capacity and 42,000 BTU cooling output, it handles typical mid-size residential loads efficiently.

Performance figures show a 96% AFUE furnace that converts nearly all fuel to usable heat, paired with a 13 SEER air conditioner using R410A refrigerant. The multi-speed blower motor runs at variable speeds rather than full-blast cycles, reducing runtime noise and improving temperature consistency. At maximum output, the system delivers 2000 CFM through ductwork, suitable for homes with 1500-2000 square feet of conditioned space.

Pros & Cons

Pros

  • 96% AFUE furnace exceeds minimum standards and reduces heating bills noticeably compared to 80% legacy systems
  • 13 SEER cooling efficiency strikes balance between performance and cost, typical for mid-range residential units
  • Multi-speed blower motor improves comfort by reducing temperature swings compared to single-stage designs
  • Flexible R410A/R22 refrigerant compatibility eases regional sourcing and maintenance
  • PVC exhaust capability simplifies venting in modern homes without metal chimney infrastructure
  • 10-year parts warranty with registration provides meaningful protection at no additional cost

Cons

  • Single-stage burner and compressor mean no efficiency modulation at partial loads, consuming more gas during mild weather
  • 75 dB noise level is louder than high-efficiency variable-speed competitors, noticeable to some homeowners
  • 13 SEER rating trails modern systems achieving 16+ SEER, limiting long-term energy savings

Who Should Buy

Best For

Homeowners in moderate climates replacing 15+ year old systems who prioritize upfront savings over premium efficiency, and contractors stocking reliable baseline equipment for residential service calls. This system makes sense where utility rates are reasonable and the home's existing ductwork won't support higher-end variable-speed components.

Consider Alternatives If

Energy-conscious buyers in cold climates or high-cost utility markets should explore 95+ SEER two-stage or modulating systems, as the payback period on this unit extends beyond 12 years in those applications.

3.5 Ton 13 SEER 96% AFUE 120,000 BTU Goodman Gas F
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Installation

Installation requires standard 115V single-phase 60Hz power with breaker sizing between 23.9 and 40 amps. The downflow configuration uses sweat-type valve connections with 3/8 inch liquid and 7/8 inch suction lines. PVC exhaust venting routes flue gases safely outside. Most installations take one day for experienced technicians familiar with Goodman equipment.

Warranty & Reliability

Goodman backs this system with a 10-year parts warranty activated through online registration. Coverage includes compressor, heat exchanger, and coil failures. Labor costs fall on the homeowner unless purchased through a contractor offering extended service agreements. This warranty length matches mid-tier industry standards.

Specifications

SKULS38783830
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)75
Weight (in lbs)30.000000
FeatureSpec
Energy StarNo
SEER1 (Efficiency)13
Condenser StagesSingle Stage
Compressor TypeReciprocating
Liquid Line3/8"
Suction Line7/8"
Liquid Valve Size3/8"
Max Breaker Size40 amps
Min. Breaker Size23.9 amps
Tonnage5 Ton
Valve TypeSweat
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.
Airflow DirectionDownflow/Horizontal
Exhaust Flue RequirementPlastic / PVC
Furnace Efficiency / AFUE96%
Blower MotorMulti Speed
Maximum CFM2000
ConfigurationUpflow / Downflow
Flue LocationRight
Burner StagesSingle
Fuel TypeGas
StyleA-Coil
Suction Line Insulation Thickness3/8"
Length30 feet

Frequently Asked Questions

How does 96% AFUE compare to my current furnace efficiency? +
If your furnace is over 15 years old, it likely runs 78-82% AFUE. A 96% unit cuts heating fuel consumption by roughly 14-18%, translating to 300-500 dollars annual savings depending on gas prices and climate. Payback typically occurs within 5-7 years.
Can this downflow unit fit in my basement with limited space? +
Yes, the downflow design measures 30 inches tall, 24.5 inches wide, and 21 inches deep, making it compatible with most basement mechanical closets. Confirm PVC exhaust venting can route safely outside before purchase.
Is 13 SEER cooling efficiency good enough? +
13 SEER meets federal minimum standards for new units but trails modern 16-18 SEER systems. For climates with 500+ cooling hours annually, upgrading to higher SEER saves money long-term despite higher upfront costs.
How does this compare to Lennox or Carrier at similar price points? +
Goodman delivers identical efficiency ratings at lower cost by simplifying design and reducing dealer markup. Higher-tier brands offer quieter operation and extended warranties, but raw performance per dollar favors Goodman for budget buyers.
What happens if components fail after the warranty ends? +
Parts become your responsibility after 10 years. Compressor replacement typically costs 800-1500 dollars; heat exchanger repair runs 600-1200 dollars. Consider purchasing extended service plans at installation for peace of mind.

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