3 Ton 17 SEER 97% AFUE 80,000 BTU Goodman Gas Furnace and Air Conditioner System - Horizontal Review 2026

// Bottom Line

This 3.5-ton horizontal system excels for homeowners upgrading from older furnaces or replacing undersized equipment, particularly in moderate climates where heating and cooling loads are balanced. The 97% AFUE and 18 SEER1 ratings deliver serious energy savings, making it ideal for budget-conscious buyers who value efficiency without premium pricing.

Review

The Goodman 3.5-ton horizontal gas furnace and air conditioner system represents solid mid-market positioning in the residential HVAC landscape. This unit combines proven Goodman reliability with modern efficiency standards, targeting homeowners and contractors seeking dependable heating and cooling without premium brand pricing. The horizontal A-coil configuration suits attic or basement installations where space constraints require a compact footprint.

Performance metrics stand out across both heating and cooling. The furnace delivers 80,000 BTU of heating output with exceptional 97% AFUE rating, meaning 97 cents of every energy dollar converts to usable heat. The cooling side produces 35,000 BTU with an impressive 18 SEER1 efficiency rating, surpassing the advertised 17 SEER specification. The modulating burner and two-stage scroll compressor work together to minimize energy waste while maintaining consistent comfort.

Pros & Cons

Pros

Exceptional 97% AFUE heating efficiency reduces gas consumption and monthly bills significantly
18 SEER1 cooling rating outperforms the 17 SEER advertised, offering Energy Star certification
Modulating burner stages deliver precise heat output, improving comfort and reducing short-cycling
Variable-speed ECM blower motor adjusts airflow automatically, enhancing efficiency across seasons
Two-stage scroll compressor handles capacity modulation smoothly for quieter operation at 71 dB

Cons

Price of $89 appears significantly below market rate, suggesting this may be a base unit price without installation or complete system components
Horizontal configuration requires proper clearance and ductwork planning, limiting placement flexibility
Requires PVC plastic flue exhaust, which adds installation complexity and material costs

Who Should Buy

Best For

Homeowners in climate zones 4-7 upgrading from 10-year-old furnaces or replacing undersized 2-ton systems will see substantial heating bill reductions with this 80,000 BTU unit. Contractors and HVAC dealers looking for reliable mid-tier inventory with strong efficiency ratings at accessible pricing should evaluate this system.

Consider Alternatives If

Buyers in extreme cold climates needing 100,000+ BTU capacity or those with limited horizontal ductwork space should explore alternatives, as this 3.5-ton capacity may not meet extreme heating demands.

3 Ton 17 SEER 97% AFUE 80,000 BTU Goodman Gas Furn

$89

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Installation

Installation requires standard refrigerant line connections using 3/8 inch liquid and 7/8 inch suction lines, both sized appropriately for this tonnage. The unit operates on standard 115V single-phase 60Hz power with a 21.3 to 35 amp breaker requirement, fitting most residential electrical panels. PVC plastic flue venting is mandatory, necessitating proper combustion air supply design and exhaust routing.

Warranty & Reliability

Goodman provides 10 years of parts coverage when registered online following purchase. This warranty period is competitive in the mid-tier segment and covers compressor, heat exchanger, and component failures. Registration is straightforward but required, so buyers should prioritize completing this step immediately after installation.

Specifications

SKU	LS38783850
Brand/Manufacturer	Online Supply
Cooling BTU	35,000
Heating BTU	80,000
Refrigerant	R410A or R22
Electrical	115 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	71
Weight (in lbs)	30.000000
Feature	Spec
Product Features	Rebate Available
Energy Star	Yes
SEER1 (Efficiency)	18
Condenser Stages	Two Stage
Compressor Type	Scroll
Liquid Valve Size	3/8"
Suction Valve Size	3/4"
Max Breaker Size	35 amps
Min. Breaker Size	21.3 amps
Tonnage	3.5 Ton
Valve Type	Sweat
Height	21"
Width	21.125"
Depth	26"
Resources	CHPF Installation Manual CHPF Specifications Sheet Goodman Evaporator Coil Warranty You will need Adobe® Acrobat® 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.
AHRI Certificate Number	7424271
Airflow Direction	Downflow/Horizontal
Exhaust Flue Requirement	Plastic / PVC
Furnace Efficiency / AFUE	97%
Blower Motor	Variable Speed - ECM
Maximum CFM	1600
Configuration	Horizontal
Flue Location	Right
Burner Stages	Modulating
Fuel Type	Propane, Natural Gas
Liquid Line	3/8"
Suction Line	7/8"
Style	A-Coil
Suction Line Insulation Thickness	3/4"
Length	50 feet

Frequently Asked Questions

How does the 18 SEER1 rating compare to standard SEER2 measurements I see elsewhere? +

SEER1 and SEER2 use different testing protocols. SEER1 typically reads higher than equivalent SEER2 ratings. This unit's 18 SEER1 roughly equals approximately 14-15 SEER2, which remains strong efficiency for mid-tier systems and comfortably exceeds Energy Star thresholds.

Can I use this horizontal unit in a downflow configuration, or does it strictly work horizontally? +

This unit is specifically designed for horizontal operation with downflow capability, meaning return air enters from above and discharge exits below. Attempting vertical installation would compromise drainage, heat exchanger function, and warranty coverage. Verify your ductwork layout matches horizontal flow patterns.

What does the modulating burner actually do for my heating costs? +

Modulating burners vary flame intensity between roughly 40-100% output based on actual heating demand, rather than cycling fully on and off like single-stage burners. This reduces temperature swings, improves comfort, and saves approximately 5-10% on heating fuel compared to non-modulating systems.

Is this unit compatible with my existing ductwork sized for a 3-ton system? +

The 3.5-ton capacity with 1600 CFM maximum airflow is slightly larger than standard 3-ton systems. Your existing ductwork may cause slight pressure drops and reduced efficiency. A professional HVAC technician should verify duct sizing before installation to ensure optimal performance.

What happens if I don't register for the warranty within the required timeframe? +

Goodman requires online registration to activate the 10-year coverage. Failure to register typically results in reduced coverage, often dropping to 5 years or limited parts availability. Always register immediately after installation through Goodman's website.

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