3.5 Ton 14 SEER 96% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Horizontal Review 2026

// Bottom Line

This Goodman system works best for contractors installing horizontal units in attics or crawlspaces where space and PVC venting are available. It balances solid heating efficiency (96% AFUE) with respectable cooling performance (16 SEER2) at a price point that won't break the budget.

Review

Goodman's 3.5-ton gas furnace and air conditioner system targets the middle market where reliability matters more than cutting-edge features. The horizontal configuration makes it ideal for attic and crawlspace installations that dominate replacement projects across the country. At 120,000 BTU heating and 42,000 BTU cooling capacity, it handles typical three-ton applications. Online Supply positions this as a balanced option for contractors and homeowners tired of budget-basement equipment but unwilling to pay premium prices.

The 96% AFUE rating puts heating efficiency in the high-efficiency category, meaning less wasted heat up the flue. Cooling performance hits 16 SEER2, which translates to real energy savings in summer months. The multi-speed ECM blower motor adjusts between 0 and 2000 CFM, allowing the system to match actual heating and cooling demand rather than running at fixed speed. Two-stage burner operation reduces temperature swings during mild weather when full 120,000 BTU capacity isn't needed.

Pros & Cons

Pros

96% AFUE heating efficiency cuts gas costs significantly compared to 80-92% units
16 SEER2 cooling rating means lower summer electricity bills for three-ton-class systems
Multi-speed ECM blower motor adapts airflow from 0-2000 CFM for comfort and efficiency
Two-stage burner reduces temperature swings and fuel waste during partial-load operation
Energy Star certified, qualifying for some utility rebates and tax incentives
10-year parts warranty with free online registration offers decent long-term protection

Cons

73 dBA noise level is louder than premium models, noticeable in basements or living spaces
Requires PVC venting only, limiting installation flexibility in older homes with masonry chimneys
Single-stage condenser means cooling cycles on and off rather than modulating for efficiency
208/230V single-phase electrical requirement needs verification on some older home panels

Who Should Buy

Best For

Contractors replacing furnaces in horizontal applications where attic or crawlspace installation is planned, and homeowners in moderate climates seeking reliable heating without premium pricing. This unit suits properties with accessible horizontal space and modern electrical service.

Consider Alternatives If

Homeowners needing quiet operation, those limited to masonry chimney venting, or anyone in extreme climates where variable-capacity cooling would significantly reduce usage costs.

3.5 Ton 14 SEER 96% AFUE 120,000 BTU Goodman Gas F

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Installation

This horizontal unit requires PVC or plastic exhaust venting, eliminating masonry chimney options. Right-side flue placement dictates ductwork layout. Electrical demands include 208/230V single-phase 60Hz service with breaker sizing between 23.5 and 40 amps, depending on how it's connected. A-coil design fits standard return air plenums. Weight at 48 pounds and dimensions (36.25 by 35.5 by 35.5 inches) fit most attic and crawlspace locations.

Warranty & Reliability

The 10-year parts warranty covers manufacturing defects after free online registration. This protects against compressor failure, heat exchanger cracks, and blower motor issues during the critical first decade. Labor and refrigerant are not included, so contractors should discuss service contract options. Goodman's warranty is solid but not exceptional compared to industry leaders offering 12-year or lifetime coverage.

Specifications

SKU	LS381183850
Brand/Manufacturer	Online Supply
Cooling BTU	42,000
Heating BTU	120,000
Refrigerant	R410A
Electrical	208 / 230 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	73
Weight (in lbs)	48.000000
Feature	Spec
Airflow Direction	Upflow/Horizontal
Exhaust Flue Requirement	Plastic / PVC
Furnace Efficiency / AFUE	96%
Blower Motor	Multi-Speed - ECM
Maximum CFM	2000
Configuration	Horizontal
Flue Location	Right
Energy Star	Yes
Burner Stages	Two
Fuel Type	Gas
Height	36.25"
Width	35.5"
Depth	35.5"
Resources	Goodman Brochure Goodman Specifications Goodman Installation Manual Goodman Warranty Information 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	1 1/8"
Tonnage	3.5 Ton
Style	A-Coil
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	23.5 amps
Suction Line Insulation Thickness	1/2"
Length	50 feet

Frequently Asked Questions

What does 96% AFUE actually save compared to standard 80% furnaces? +

On a 120,000 BTU furnace running through a heating season, 96% AFUE converts 96 cents of every fuel dollar to heat while 80% only converts 80 cents. A typical household saves $200-400 annually in colder climates. In southern regions, savings are smaller but still meaningful over the furnace's 15-20 year lifespan.

Can I install this in a basement or closet instead of horizontal attic position? +

The horizontal configuration is optimized for attic or crawlspace mounting where gravity returns air upward. Closet or basement upflow installations require different models. Always verify airflow direction with your installer before ordering, as returning wrong equipment wastes time and money.

How does 16 SEER2 cooling compare to current high-efficiency models? +

16 SEER2 represents solid mid-tier cooling efficiency. Premium systems reach 20+ SEER2 but cost significantly more. For moderate climates with 50-100 cooling days annually, the difference in energy bills is modest, making this unit sensible if heating is the priority.

Is Goodman equipment as reliable as Carrier or Lennox? +

Goodman owns the reliability reputation for competitive pricing, not industry-leading uptime. Independent repair data shows similar failure rates after 10 years. The brand works fine for price-conscious buyers but premium manufacturers show marginally better long-term records.

What does the 10-year warranty actually cover? +

Parts only, not labor or refrigerant. Compressor, heat exchanger, and blower motor defects are covered after online registration. You pay service calls and technician time. Read the full warranty document before assuming coverage for your specific failure.

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