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 is ideal for contractors installing attic or crawlspace units where space is tight and efficiency matters. The 96% AFUE heating paired with 14 SEER cooling delivers solid year-round performance at a competitive price point, especially valuable in moderate climates where both seasons run regularly.

Review

The Goodman 3.5 Ton system occupies a practical middle ground in the HVAC market, targeting contractors who need dependable equipment without premium pricing. This horizontal configuration addresses a real installation challenge, fitting where vertical furnaces won't work. Goodman's reputation for straightforward, serviceable equipment means technicians can find parts and support readily. The combination of 96% AFUE furnace heating with 14 SEER cooling positions it as a solid mid-tier choice for residential retrofit work.

The 96% AFUE rating means this furnace converts nearly all fuel to usable heat, a meaningful step above standard 80-85% units. Heating output reaches 120,000 BTU with single-stage burner operation. Cooling delivers 42,000 BTU at 14 SEER using a scroll compressor and R410A or R22 refrigerant. The multi-speed blower motor maxes out at 2,000 CFM, allowing technicians to tune airflow for comfort. Operating at 73 dB puts it in the moderate noise range for furnaces.

Pros & Cons

Pros

96% AFUE furnace efficiency reduces heating costs compared to 80-90% baseline models
14 SEER cooling rating matches mid-tier efficiency standards for air conditioning
Horizontal configuration fits attics and tight spaces where vertical units won't fit
PVC exhaust compatibility simplifies installation in modern homes without masonry chimneys
Multi-speed blower motor provides better comfort control than single-speed alternatives
10-year warranty with online registration covers major components

Cons

Single-stage burner and single-stage compressor limit efficiency gains in part-load conditions
73 dB noise level runs louder than some competitors, notable in attic installations
Not Energy Star certified despite respectable 14 SEER rating
5-ton tonnage creates sizing mismatch with advertised 3.5-ton capacity, creating confusion

Who Should Buy

Best For

Contractors and homeowners upgrading older furnaces in attic or horizontal crawlspace applications will find this unit practical and cost-effective. It works well in climates with moderate heating and cooling seasons where 96% AFUE and 14 SEER provide real savings without premium pricing.

Consider Alternatives If

Buyers in extremely tight spaces needing ultra-quiet operation or those seeking maximum efficiency (18+ SEER) should evaluate alternatives with variable-stage compressors and better sound dampening.

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

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Installation

Horizontal mounting requires proper ductwork clearance above and below the unit's compact 24.5-inch height and 26-inch width. PVC exhaust simplifies venting compared to metal flue requirements. The unit draws 208-230V single-phase power with breaker sizing between 22-35 amps depending on load. Technicians should verify attic framing can support the 30-pound weight and ensure adequate air return paths for the 2,000 CFM maximum airflow.

Warranty & Reliability

Online registration unlocks a 10-year parts warranty covering the compressor, heat exchanger, and major components. This is competitive for equipment at this price tier. Registration is required, so buyers must complete this step after installation. The warranty does not cover labor or refrigerant, standard limitations in the industry.

Specifications

SKU	LS38783830
Brand/Manufacturer	Online Supply
Cooling BTU	42,000
Heating BTU	120,000
Refrigerant	R410A or R22
Electrical	208 / 230 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	73
Weight (in lbs)	30.000000
Feature	Spec
Airflow Direction	Upflow/Horizontal
Exhaust Flue Requirement	Plastic / PVC
Furnace Efficiency / AFUE	96%
Blower Motor	Multi Speed
Maximum CFM	2000
Configuration	Horizontal
Flue Location	Right
Burner Stages	Single
Fuel Type	Gas
Height	24.5"
Width	26"
Depth	21.125"
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.
Energy Star	No
SEER1 (Efficiency)	14
Condenser Stages	Single Stage
Compressor Type	Scroll
Liquid Valve Size	3/8"
Suction Valve Size	7/8"
Max Breaker Size	35 amps
Min. Breaker Size	22 amps
Tonnage	5 Ton
Liquid Line	3/8"
Suction Line	7/8"
Style	A-Coil
Suction Line Insulation Thickness	3/8"
Length	30 feet

Frequently Asked Questions

Why does the spec sheet list 5 tons when this is advertised as 3.5 tons? +

The 5-ton tonnage refers to the condensing unit cooling capacity. The system is positioned as 3.5 tons because that's the matched pair rating when combined with standard evaporator coils. The 42,000 BTU cooling output supports this sizing, though capacity depends on proper charge and airflow.

Can I install this in an attic, and what venting do I need? +

Yes, the horizontal configuration is designed for attics. PVC exhaust piping must extend through the roof or side wall following local code. Ensure at least 6 inches of clearance around the unit and secure it to prevent vibration. Your HVAC contractor should verify proper combustion air supply.

How does 14 SEER compare to modern cooling equipment? +

14 SEER is solid mid-range efficiency. Current standards range from 13-22 SEER depending on climate zones. This unit will reduce summer energy use versus 13 SEER baseline but trails high-efficiency models. Total savings depend on your local electricity rates and cooling season length.

Is this better than a standard 80% AFUE furnace plus window AC? +

Yes, significantly. 96% AFUE furnaces save roughly 16% on heating fuel compared to 80% units. Paired cooling at 14 SEER beats window units' typical 10-11 SEER. A complete integrated system also improves comfort through consistent airflow and single thermostat control.

What does the 10-year warranty actually cover? +

The 10-year warranty covers the compressor, heat exchanger, and sealed components after online registration. Labor is not included. Most repairs at year 1-5 are covered, though homeowners may see higher out-of-pocket costs after year 7.

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