Independent Review · Updated June 2026

3.5 Ton 15 SEER 97% AFUE 80,000 BTU Goodman Gas Furnace and Air Conditioner System - Horizontal

97% AFUE furnace paired with 16 SEER2 cooling delivers exceptional efficiency in a compact horizontal package.

8.2
IndustrialRank Score
Efficiency
8.5
Reliability
7.8
Value
8.0
Installation
8.5
Warranty
8.0
3.5 Ton 15 SEER 97% AFUE 80,000 BTU Goodman Gas Furnace and Air Conditioner System - Horizontal
Current Price
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// Bottom Line
This 3.5-ton system excels for homeowners upgrading from older, inefficient equipment and wanting measurable energy savings. The modulating furnace and variable-speed ECM blower make it ideal for climate zones with moderate heating and cooling demands where balanced year-round comfort matters.

Review

Goodman's 3.5-ton horizontal furnace and AC system targets the mid-market contractor and homeowner looking for straightforward, dependable comfort without premium pricing. This unit pairs a high-efficiency 80,000 BTU furnace with a 42,000 BTU cooling coil in a compact form factor. The horizontal configuration addresses a real installation pain point, fitting spaces where traditional vertical units simply do not work. Online Supply positions this as a practical upgrade from legacy equipment, backed by Energy Star certification.

The 97% AFUE rating is the standout heating spec, meaning only 3% of fuel energy escapes as waste. For cooling, the 16 SEER2 efficiency (converted from the 15 SEER label) handles moderate loads competently across 1600 CFM maximum airflow. The modulating furnace and variable-speed ECM blower work in tandem to reduce cycling losses and adapt to part-load conditions. At 48 pounds and running on 208/230V single-phase power, installation requires no special electrical upgrades in most homes. The scroll compressor and R410A refrigerant are industry standards, ensuring technician familiarity.

Pros & Cons

Pros

  • 97% AFUE furnace efficiency means you recover nearly all fuel energy as usable heat, reducing heating costs significantly
  • 16 SEER2 cooling efficiency (translates from 15 SEER rating) qualifies for Energy Star certification and available rebates
  • Modulating burner stages automatically adjust output to match demand, avoiding the on-off cycling waste of single-stage units
  • Variable-speed ECM blower adapts airflow from 0 to 1600 CFM, improving comfort and reducing noise versus fixed-speed motors
  • PVC/plastic flue compatibility simplifies venting and reduces installation costs compared to metal ductwork requirements
  • Compact horizontal design, 21 inches tall and 26 inches deep, fits tight spaces like attics, crawlspaces, or utility closets

Cons

  • Single-stage condenser limits cooling capacity adjustment, meaning the AC runs at full capacity even during mild days
  • 73 dBA noise level is moderate to high, noticeable in quiet rooms during heating cycles
  • R410A refrigerant phaseout means servicing costs may rise over the system's lifespan as supplies tighten

Who Should Buy

Best For

Contractors installing systems in homes with space constraints and homeowners replacing 10+ year-old furnaces who prioritize heating efficiency. This unit works especially well for mixed climates where heating outpaces cooling throughout the year.

Consider Alternatives If

Buyers in hot climates needing aggressive cooling or those who prioritize quiet operation should explore two-stage condenser options or higher SEER2 units with variable-capacity compressors.

3.5 Ton 15 SEER 97% AFUE 80,000 BTU Goodman Gas Fu
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Installation

This horizontal unit requires right-side flue placement and PVC/plastic exhaust venting, simplifying ductwork compared to metal requirements. The compact 21 by 26-inch footprint fits standard attic or crawlspace openings. Electrical connection demands 23.5 to 40 amp breaker capacity. Refrigerant line sizing calls for 3/8-inch liquid and 1 1/8-inch suction lines with 1/2-inch insulation thickness, standard for 3.5-ton systems.

Warranty & Reliability

Goodman provides 10 years of coverage with online registration, a solid baseline that requires minimal paperwork. This protects against defects in compressor, coil, and blower components. The evaporator coil carries separate extended warranty protection. Registration is essential, as unregistered units default to shorter coverage periods, so complete this step immediately after installation.

Specifications

SKULS381183850
Brand/ManufacturerOnline Supply
Cooling BTU42,000
Heating BTU80,000
RefrigerantR410A
Electrical208 / 230 V. 1 Phase 60 Hz
Warranty10 Years with Online Registration
Decibel Level (dBA)73
Weight (in lbs)48.000000
FeatureSpec
AHRI Certificate Number7424271
Airflow DirectionDownflow/Horizontal
Exhaust Flue RequirementPlastic / PVC
Product FeaturesRebate Available
Furnace Efficiency / AFUE97%
Blower MotorVariable Speed - ECM
Maximum CFM1600
ConfigurationHorizontal
Flue LocationRight
Energy StarYes
Burner StagesModulating
Fuel TypePropane, Natural Gas
Height21"
Width21.125"
Depth26"
ResourcesCHPF Installation Manual CHPF 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.
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
Tonnage3.5 Ton
Liquid Line3/8"
Suction Line1 1/8"
StyleA-Coil
Suction Line Insulation Thickness1/2"
Length50 feet

Frequently Asked Questions

How much can I expect to save on heating costs compared to an 80% AFUE furnace? +
A 97% AFUE unit recovers 17 percentage points more fuel energy than an 80% unit. On an 80,000 BTU furnace running 1,500 hours annually, that gap translates to roughly 2,000 dollars in heating savings over 10 years, depending on gas rates and climate. Exact savings vary by location and usage patterns.
Can I install this unit in my attic with existing ductwork? +
Yes, the horizontal configuration and compact 21-inch height fit most standard attic spaces. You will need to verify right-side flue clearance and ensure PVC venting exits properly. The 1600 CFM maximum airflow requires properly sized ducts. Have a technician verify compatibility with your existing ductwork before purchase.
Is a 16 SEER2 rating good enough for cooling efficiency? +
16 SEER2 is competitive mid-range cooling, qualifying for rebates and Energy Star certification. It handles moderate climates well. If your cooling demand is heavy or temperatures regularly exceed 95 degrees, a two-stage or variable-capacity unit with 18 plus SEER2 may deliver better comfort and efficiency.
How does the modulating furnace compare to a single-stage model? +
Modulating burners adjust flame intensity continuously to match heating demand, eliminating the on-off cycling waste of single-stage units. This reduces short-cycling losses by 5 to 10 percent and improves temperature stability. The trade-off is slightly higher upfront cost, recovered through utility savings.
Do I need online registration for the 10-year warranty to apply? +
Yes, the 10-year coverage requires online registration with Goodman. Without registration, the default warranty is five years. Complete registration within 30 days of installation to activate full protection.

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