3 Ton 13 SEER 80% AFUE 100,000 BTU Goodman Gas Furnace and Air Conditioner System - Horizontal Review 2026

// Bottom Line

This Goodman system works best for contractors installing replacement HVAC in residential properties where horizontal configuration fits existing ductwork and budget constraints matter. The 80% AFUE efficiency and 13 SEER cooling deliver acceptable performance without premium pricing, making it ideal for middle-market renovation projects rather than high-efficiency new builds.

Review

The Goodman 3 Ton 13 SEER gas furnace and air conditioner system represents the practical middle ground in residential HVAC, trading premium efficiency for accessible pricing and installation flexibility. Manufactured by Online Supply, this horizontal-mount configuration delivers 100,000 BTU heating and 36,000 BTU cooling capacity in a compact 27.5 by 26 by 26 inch footprint. It competes in the value segment where contractors prioritize compatibility and contractors over cutting-edge performance.

Performance metrics show respectable but not exceptional efficiency. The 80% AFUE furnace rating means 80 cents of every dollar spent on fuel converts to usable heat, losing 20% up the flue. Cooling efficiency of 13 SEER1 aligns with mid-2010s standards. The reciprocating compressor operates at single stage, while the furnace uses two-stage burners to reduce on-off cycling. Variable-speed blower technology at 2,000 CFM maximum helps optimize part-load efficiency compared to fixed-speed alternatives.

Pros & Cons

Pros

Variable speed blower motor manages airflow at 2,000 CFM maximum, reducing energy waste during partial-load operation
Two-stage burner provides better modulation than single-stage units, improving comfort and efficiency in fluctuating demand
Horizontal A-coil configuration fits tight attic and crawlspace installations where vertical setups won't work
Dual fuel capability handles both natural gas and propane without modification, useful for rural or mixed-fuel regions
10-year warranty with online registration provides solid coverage for parts and labor peace of mind

Cons

80% AFUE is dated by today's standards, missing Energy Star qualification and losing ground to 95% AFUE high-efficiency models
13 SEER1 cooling efficiency trails newer 16+ SEER systems, resulting in higher summer operating costs
74 dB noise level sits at the louder end for residential use, potentially noticeable during heating cycles

Who Should Buy

Best For

Contractors handling mid-range residential replacements and cost-conscious homeowners in moderate climates where maximum efficiency matters less than reliable performance and upfront affordability. This unit also suits properties with existing horizontal ductwork or tight installation spaces where standard vertical furnaces don't fit.

Consider Alternatives If

Homeowners in extreme climates or those pursuing utility rebates should consider 95% AFUE furnaces and 16+ SEER air conditioners instead, as long-term energy savings justify the higher initial investment.

3 Ton 13 SEER 80% AFUE 100,000 BTU Goodman Gas Fur

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Installation

Horizontal installation requires proper ductwork clearance and support framing for the 30-pound unit. The 208/230V single-phase 60Hz electrical connection demands a dedicated 19.1 to 30-amp breaker, necessitating electrician involvement on older panels. Metal exhaust flue requirement adds installation cost. Refrigerant lines use 3/8 inch liquid and 7/8 inch suction connections with 3/8 inch insulation thickness, standard for most residential applications.

Warranty & Reliability

Goodman provides a 10-year warranty when customers complete online registration, covering compressor and major components. This matches industry standard for mid-tier systems. Warranty terms protect against manufacturing defects but exclude routine maintenance and wear items. Registration is straightforward and unlocks the full coverage period versus the reduced baseline warranty for unregistered units.

Specifications

SKU	LS38783830
Brand/Manufacturer	Online Supply
Cooling BTU	36,000
Heating BTU	100,000
Refrigerant	R410A
Electrical	208 / 230 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	74
Weight (in lbs)	30.000000
Feature	Spec
Airflow Direction	Upflow/Horizontal
Exhaust Flue Requirement	Metal
Furnace Efficiency / AFUE	80%
Blower Motor	Variable Speed
Maximum CFM	2000
Configuration	Horizontal
Burner Stages	Two
Fuel Type	Propane, Natural Gas
Height	27.5"
Width	26"
Depth	26"
Resources	Goodman Installation Manual Goodman Specifications Goodman Technical Manual Goodman Warranty Information Goodman Brochure Goodman Service Instructions Goodman Kit Instructions Goodman Parts Manual 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.
Liquid Line	3/8"
Suction Line	7/8"
Tonnage	3 Ton
Style	A-Coil
Replaces	GSX130362, GSX130363, GSX130365
Energy Star	No
SEER1 (Efficiency)	13
Condenser Stages	Single Stage
Compressor Type	Reciprocating
Liquid Valve Size	3/8"
Suction Valve Size	3/4"
Max Breaker Size	30 amps
Min. Breaker Size	19.1 amps
Valve Type	Sweat
Suction Line Insulation Thickness	3/8"
Length	30 feet

Frequently Asked Questions

Can this furnace use both natural gas and propane interchangeably? +

Yes, this unit handles both fuels but requires burner adjustment during installation. You cannot switch between fuels without professional recalibration. Contractor must order the correct kit and perform setup according to Goodman's installation manual. Propane conversions typically demand slightly different orifices and settings than natural gas operation.

Is horizontal mounting suitable for attic installation above living spaces? +

Yes, horizontal configuration fits attic applications where vertical furnaces won't work. However, verify adequate return and supply ductwork clearance before purchase. Horizontal units need proper vibration isolation pads and support to prevent noise transmission into occupied rooms below. The 74 dB output should be assessed against noise sensitivity.

How does 80% AFUE compare to modern high-efficiency options? +

80% AFUE loses significantly to current 95% AFUE models, wasting 15% more fuel annually. Over 20 years, a household using 100 million BTU yearly spends approximately $3,000 more on heating with this unit versus 95% AFUE. Modern options offer condensing technology that recovers exhaust heat, making them superior despite higher upfront costs.

Should I choose this over a 16 SEER air conditioner system? +

The 13 SEER1 rating here trails newer 16 SEER systems by roughly 20% cooling efficiency. In hot climates running AC six months yearly, the efficiency gap translates to $400 to $800 additional annual cooling costs. This Goodman suits moderate climates where heating dominates seasonal demand, favoring the two-stage furnace investment over premium cooling capacity.

What does the 10-year warranty actually cover? +

Compressor, refrigerant, and sealed components receive full parts coverage for ten years with registration. Labor coverage varies by manufacturer authorized service plans. The warranty excludes ductwork, electrical wiring, installation mistakes, and preventive maintenance like filter changes. Verify local contractor participation in Goodman's warranty network before purchase.

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