Independent Review · Updated June 2026

3 Ton 15 SEER 97% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Horizontal

97% AFUE furnace with variable-speed blower and modulating burner for precise heating

8.2
IndustrialRank Score
Efficiency
8.5
Reliability
7.8
Value
8.0
Installation
8.5
Warranty
8.0
3 Ton 15 SEER 97% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Horizontal
Current Price
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// Bottom Line
This Goodman horizontal furnace is ideal for contractors and homeowners upgrading existing systems in tight attic or basement spaces where efficient heating and cooling matter. The 97% AFUE rating and modulating burner deliver measurable energy savings on natural gas or propane.

Review

The Goodman 3-ton horizontal gas furnace ranks among the better mid-tier options for residential heating and cooling. Rated at 97% AFUE with 120,000 BTU heating output, it combines efficient combustion with a variable-speed blower motor that adapts to real-time demand. The horizontal configuration (24.5 inches tall, 26 inches wide, 21.125 inches deep) solves installation challenges in tight attics or basement crawlspaces where standard upflow units won't fit. Goodman's reputation for solid build quality and the 10-year warranty make this a practical choice for contractors and budget-conscious homeowners.

Performance data tells the real story. The 97% AFUE rating means nearly all fuel converts to usable heat, translating to lower monthly gas bills versus standard 80-90% units. The modulating burner operates at multiple flame levels rather than simple on-off cycling, cutting temperature overshooting and short-cycling. On cooling, 34,800 BTU output with a scroll compressor delivers 16 SEER1 efficiency, adequate for many climates though not exceptional. The variable-speed blower motor ramps from idle to 2,000 CFM based on heating and cooling load, improving system responsiveness and reducing cycling losses.

Pros & Cons

Pros

  • 97% AFUE furnace efficiency minimizes fuel waste and monthly heating bills on natural gas or propane
  • Modulating burner adjusts flame output in real time rather than cycling on/off, reducing temperature swings
  • Variable-speed ECM blower motor ramps up or down based on demand, improving comfort and reducing energy use
  • ENERGY STAR certified with 10-year warranty including online registration
  • Horizontal configuration (24.5 inches tall, 26 inches wide) fits tight attic or basement installations

Cons

  • Cooling efficiency is 16 SEER1, which is solid but not ultra-high tier like 18+ SEER systems
  • Single-stage condenser means the AC unit runs at full capacity or off, with no intermediate cooling levels
  • 73.5 dB noise level is moderately loud, noticeable during operation in finished spaces

Who Should Buy

Best For

Contractors replacing worn furnaces in existing homes with space constraints, and homeowners in moderate to cold climates who prioritize heating efficiency and comfort control. The modulating burner works especially well for variable outdoor temperatures.

Consider Alternatives If

Anyone seeking premium cooling efficiency above 18 SEER, or homes with sound-sensitive zones where low-noise operation is critical.

3 Ton 15 SEER 97% AFUE 120,000 BTU Goodman Gas Fur
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Installation

This furnace requires 208/230V single-phase power with a minimum 18.7-amp breaker and maximum 30-amp breaker size, making it compatible with standard residential electrical service. It uses plastic or PVC flue exhaust, simplifying venting through exterior walls. The horizontal design requires proper condensate drain routing. Professional installation is strongly recommended to verify refrigerant charge, airflow, and gas line pressure, especially when converting from older equipment.

Warranty & Reliability

Goodman provides a 10-year parts warranty when registered online after installation, covering both furnace and evaporator coil components. This warranty protects against manufacturing defects and premature compressor failure. Extended labor coverage is not included, so repair costs beyond parts depend on local service rates. Registration is simple but mandatory to activate full coverage.

Specifications

SKULS38783850
Brand/ManufacturerOnline Supply
Cooling BTU34,800
Heating BTU120,000
RefrigerantR410A or R22
Electrical208 / 230 V. 1 Phase 60 Hz
Warranty10 Years with Online Registration
Decibel Level (dBA)73.5
Weight (in lbs)30.000000
FeatureSpec
AHRI Certificate Number7424268
Airflow DirectionUpflow/Horizontal
Exhaust Flue RequirementPlastic / PVC
Product FeaturesRebate Available
Furnace Efficiency / AFUE97%
Blower MotorVariable Speed - ECM
Maximum CFM2000
ConfigurationHorizontal
Flue LocationRight
Energy StarYes
Burner StagesModulating
Fuel TypePropane, Natural Gas
Height24.5"
Width26"
Depth21.125"
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 Size30 amps
Min. Breaker Size18.7 amps
Tonnage5 Ton
Liquid Line3/8"
Suction Line7/8"
StyleA-Coil
Suction Line Insulation Thickness3/4"
Length50 feet

Frequently Asked Questions

Why is this a 3-ton system when the specs say 5-ton tonnage? +
The product listing has conflicting data. Industry standard uses cooling capacity (34,800 BTU equals 2.9 tons, rounded to 3-ton). The 5-ton reference may be a data error. Verify tonnage with the seller or AHRI Certificate 7424268 before purchase to confirm actual cooling capacity matches your home's load.
Can I use this in my attic if space is very tight? +
Yes, the horizontal configuration (24.5 inches tall) fits most attic joists. However, you need clearance for the right-side flue exit, condensate drain access, and airflow return paths. Have an installer measure your space before committing. Tight installations may require custom ductwork.
How much will this furnace reduce my monthly gas bill compared to an 80% AFUE unit? +
A 97% AFUE system converts 17 percentage points more fuel to heat than 80% AFUE. On a 100,000 BTU home heating load, expect roughly 17-20% lower gas costs annually. Actual savings depend on climate, thermostat settings, and current unit efficiency. Colder regions see greater dollar savings.
Is 16 SEER1 cooling efficiency good enough, or should I upgrade? +
16 SEER1 is solid mid-tier performance, qualifying for ENERGY STAR. It's adequate for most climates but trails 18+ SEER systems by 10-15% in efficiency. Choose based on climate, cooling load, and budget. Hot, humid regions benefit more from higher SEER ratings.
What does the 10-year warranty actually cover? +
Parts coverage includes the furnace, compressor, and evaporator coil when registered within 30 days of installation. Labor is not covered. Coverage excludes damage from improper installation, maintenance neglect, or refrigerant leaks due to installer error.

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