3.5 Ton 13 SEER 96% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Horizontal Review 2026

// Bottom Line

This horizontal-mounted combo system works well for contractors retrofitting residential spaces with tight layouts or homeowners needing solid mid-tier efficiency without premium pricing. The 96% AFUE furnace and 13 SEER condenser pair make it a practical choice for moderate climates where upfront cost matters as much as operating efficiency.

Review

The Goodman 3.5-ton horizontal combo system balances efficiency and affordability in a market crowded with budget units on one end and premium variable-capacity equipment on the other. This SKU combines a 120,000 BTU gas furnace with a 42,000 BTU air conditioning condenser, making it suitable for homes ranging from 1,200 to 1,600 square feet depending on insulation and climate. The horizontal orientation targets contractors and homeowners dealing with space constraints where traditional vertical casings create installation headaches.

Performance metrics are solid across both heating and cooling. The furnace achieves 96% AFUE, meaning 96 cents of every energy dollar converts to usable heat, while the air conditioner delivers 13 SEER cooling efficiency. The multi-speed blower motor pulls up to 2,000 CFM, adapting fan speed to match heating and cooling loads. Single-stage operation keeps the compressor and burner straightforward, trading variable precision for proven longevity and lower service costs.

Pros & Cons

Pros

96% AFUE furnace efficiency exceeds most single-stage gas furnaces and minimizes heating waste
13 SEER cooling delivers above-average AC performance for mid-range equipment
Horizontal configuration fits tight attic or basement spaces where vertical units won't work
Single-stage reciprocating compressor offers proven reliability with straightforward maintenance
Multi-speed blower motor optimizes airflow across heating and cooling cycles
10-year warranty with online registration provides solid coverage for parts and labor

Cons

Single-stage burner and compressor means less precise temperature control than two-stage alternatives
75 dB noise level runs louder than high-efficiency variable-speed competitors
Not ENERGY STAR certified, so buyers miss federal tax incentives in some states
Requires R410A or R22 refrigerant, limiting upgrade options as regulations shift toward lower-GWP alternatives

Who Should Buy

Best For

Contractors installing replacement systems in homes with attic or basement space constraints will appreciate the horizontal design. Homeowners in moderate climates wanting efficiency gains without premium pricing will find the 96% AFUE and 13 SEER ratings deliver strong value.

Consider Alternatives If

Buyers seeking ENERGY STAR certification, variable-capacity systems for extreme climate swings, or the lowest operational noise should look at higher-tier Goodman units or competing manufacturers.

3.5 Ton 13 SEER 96% AFUE 120,000 BTU Goodman Gas F

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Installation

This system requires 115V single-phase 60 Hz power with breaker sizing between 23.9 and 40 amps, making it compatible with standard residential electrical service. PVC or plastic exhaust flue vents heat safely outdoors with right-side flue location. Refrigerant lines use 3/8 inch liquid and 7/8 inch suction piping with sweat valve connections, and installation manuals are available through Online Supply. Horizontal mounting requires solid structural support and proper condensate drainage.

Warranty & Reliability

Coverage includes a 10-year parts warranty when you complete online registration with Online Supply. This protects compressor, heat exchanger, and major components against manufacturing defects. Labor coverage varies by installer and location. This warranty is industry-standard for Goodman mid-range equipment but falls short of extended protection offered by premium brands.

Specifications

SKU	LS38783830
Brand/Manufacturer	Online Supply
Cooling BTU	42,000
Heating BTU	120,000
Refrigerant	R410A or R22
Electrical	115 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	75
Weight (in lbs)	30.000000
Feature	Spec
Energy Star	No
SEER1 (Efficiency)	13
Condenser Stages	Single Stage
Compressor Type	Reciprocating
Liquid Line	3/8"
Suction Line	7/8"
Liquid Valve Size	3/8"
Max Breaker Size	40 amps
Min. Breaker Size	23.9 amps
Tonnage	3.5 Ton
Valve Type	Sweat
Height	24.5"
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.
Airflow Direction	Downflow/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
Style	A-Coil
Suction Line Insulation Thickness	3/8"
Length	30 feet

Frequently Asked Questions

What square footage does this 3.5-ton system handle? +

A 3.5-ton system (42,000 BTU cooling capacity) typically covers 1,200 to 1,600 square feet depending on insulation quality, climate zone, and ductwork efficiency. For hot climates or poor insulation, size down to 1,200 square feet; for mild climates with good sealing, extend toward 1,600 square feet. Always have a load calculation performed before installation.

Will this fit in a tight attic space? +

Yes. The horizontal configuration measures 24.5 inches high, 21.125 inches wide, and 26 inches deep, plus you need clearance for the 30-foot suction line insulation. Most attics can accommodate it, but verify ductwork routing and return air paths don't restrict airflow. Measure carefully before ordering.

How does 13 SEER compare to modern air conditioners? +

13 SEER is above-average for single-stage equipment but trails variable-capacity units rated 16 to 24 SEER. However, it beats budget models at 10 to 11 SEER. For moderate climates with mild summers, 13 SEER delivers solid savings without the premium cost and complexity of inverter-based systems.

Is this better than a Lennox or Carrier equivalent? +

Goodman matches Lennox and Carrier performance at lower cost but sacrifices some sound insulation and variable staging. This unit excels for budget-conscious contractors. If noise reduction or precision zoning matters more, premium brands justify higher pricing.

Does online registration actually matter for the warranty? +

Yes. The 10-year coverage requires completing online registration with Online Supply. Without registration, warranty may be limited. Register promptly after installation to avoid disputes if problems arise later.

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