4 Ton 15 SEER 96% AFUE 100,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow Review 2026

// Bottom Line

This Goodman system works best for homeowners replacing aging equipment in climates with moderate heating and cooling demands. The 96% AFUE furnace and 16 SEER condenser deliver solid efficiency gains without premium pricing, though the 100,000 BTU heating output limits it to homes under 2,500 square feet.

Review

The Goodman 4-ton (5-ton capacity rated) combo system represents a practical mid-range choice for residential HVAC replacement. This unit bundles a downflow gas furnace with an air-cooled condenser, simplifying installation for retrofit applications. Goodman positions itself as a value-oriented manufacturer, and this system reflects that philosophy. The SKU LS381183850 replaces the older GSX16S481 model with meaningful efficiency improvements across both heating and cooling modes.

Heating output reaches 100,000 BTU with 96% AFUE efficiency, meaning 96 cents of every fuel dollar converts to usable heat. Cooling delivers 45,500 BTU at 16 SEER, well above the federal minimum of 14 SEER. The variable-speed ECM blower pulls up to 2,000 CFM, distributing conditioned air evenly through ductwork. Two-stage burner operation modulates gas input for better comfort during mild weather. The scroll compressor uses R410A refrigerant and operates at 73 dB, typical for single-stage units at this tonnage.

Pros & Cons

Pros

96% AFUE furnace efficiency saves significant heating costs compared to 80-90% units
16 SEER cooling efficiency qualifies for Energy Star certification and utility rebates
Variable-speed ECM blower motor matches airflow to demand, reducing runtime and noise
Two-stage burner provides better part-load heating efficiency and comfort
10-year warranty with online registration covers parts and compressor

Cons

100,000 BTU output is undersized for homes above 2,500 square feet in cold climates
Single-stage scroll compressor cannot modulate cooling capacity like two-stage units
73 dB noise level runs slightly louder than high-efficiency variable-capacity competitors

Who Should Buy

Best For

Homeowners in moderate climates seeking to replace 15-20 year old furnace and AC units will see immediate energy savings. Contractors installing systems in new construction or modest-sized homes benefit from straightforward single-stage operation and proven Goodman reliability.

Consider Alternatives If

Buyers in extreme cold climates needing 125,000+ BTU output or those prioritizing ultra-quiet operation should evaluate higher-capacity or two-stage compressor models.

4 Ton 15 SEER 96% AFUE 100,000 BTU Goodman Gas Fur

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Installation

Downflow configuration suits basements or attics where ductwork runs below the unit. Suction line (7/8 inch) and liquid line (3/8 inch) connections accept standard refrigerant sets. Unit dimensions of 34.5 inches tall, 21 inches wide, and 28.75 inches deep fit most existing footprints. Electrical requirement is 115V single-phase at 23.9 to 40 amps, standard for residential circuits. PVC exhaust venting required for furnace flue. Suction line insulation at 1/2 inch thickness helps prevent condensation.

Warranty & Reliability

Ten-year parts and compressor warranty activates upon online registration. Coverage begins from installation date and transfers if you sell the home. Goodman's warranty is mid-range for the industry, neither premium nor budget-tier. Registration is straightforward but required to claim full coverage. This aligns with most homeowner comfort levels for a system expected to run 15-20 years.

Specifications

SKU	LS381183850
Brand/Manufacturer	Online Supply
Cooling BTU	45,500
Heating BTU	100,000
Refrigerant	R410A or R22
Electrical	115 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	73
Weight (in lbs)	48.000000
Feature	Spec
Replaces	GSX16S481
Energy Star	Yes
SEER1 (Efficiency)	16
Condenser Stages	Single Stage
Compressor Type	Scroll
Liquid Valve Size	3/8"
Suction Valve Size	7/8"
Max Breaker Size	40 amps
Min. Breaker Size	23.9 amps
Tonnage	5 Ton
Height	34.5"
Width	21"
Depth	28.75"
Resources	Goodman Brochure Goodman Installation Instructions Goodman Parts Manual Goodman Service Manual Goodman Specifications Goodman Technical Information Goodman User Information Goodman Warranty You will need AdobeÂ® AcrobatÂ® Reader to view PDF documents.
Safety Information	PROPOSITION 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.
Configuration	Downflow/Horizontal
Liquid Line	3/8"
Suction Line	1 1/8"
Style	A-Coil
AHRI Certificate Number	7368844
Airflow Direction	Downflow/Horizontal
Exhaust Flue Requirement	Plastic / PVC
Product Features	Rebate Available
Furnace Efficiency / AFUE	96%
Blower Motor	Variable Speed - ECM
Maximum CFM	2000
Burner Stages	Two
Fuel Type	Propane, Natural Gas
Suction Line Insulation Thickness	1/2"
Length	50 feet

Frequently Asked Questions

Is this system truly 4 ton if the specs say 5 ton? +

The condenser is rated 5 tons capacity, but furnace output matches 4-ton cooling at 45,500 BTU. They ship as matched pair for proper equipment sizing. The title reflects the furnace stage, which is how contractors typically specify systems.

Will this fit my current ducting and equipment location? +

At 34.5 inches tall and 28.75 inches deep, it fits standard replacement spaces. Downflow configuration works in basements and attics. Measure your existing unit's footprint and verify ceiling height. The 50-foot suction line allows flexible outdoor condenser placement.

How much will my heating bills drop versus my old unit? +

At 96% AFUE versus an average old unit at 80% AFUE, expect 20 percent less heating fuel consumption. Annual savings depends on local gas rates and heating degree days. In moderate climates, savings typically range from 200 to 400 dollars annually.

How does single-stage cooling compare to two-stage or variable units? +

Single-stage compressors run full capacity whenever cooling is needed, cycling on and off. Two-stage units modulate capacity down on mild days. Variable-capacity equipment adjusts continuously. Single-stage consumes more energy part-load but costs less upfront. Trade-off depends on your climate and comfort priorities.

What does the 10-year warranty actually cover if something fails? +

Parts and compressor replacement covered for 10 years with registration. Labor costs fall on you or your contractor. Warranty excludes damage from improper installation, lack of maintenance, or refrigerant leaks from accidents.

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