3.5 Ton 14 SEER 80% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Horizontal Review 2026

// Bottom Line

This Goodman system works well for homeowners replacing older equipment in moderate climates or those upgrading from single-stage systems. The 80% AFUE furnace and 14 SEER air conditioner deliver solid efficiency without premium pricing, making it practical for budget-conscious installations where energy savings matter more than cutting-edge performance.

Review

Goodman's horizontal gas furnace and air conditioner combination targets the practical middle ground where budget constraints meet functionality demands. At 3.5 tons cooling and 120,000 BTU heating, this system handles moderate residential loads without oversizing costs. The horizontal configuration makes it valuable for attic and basement installations where space is tight or vertical clearance limited. This isn't a premium system, but Goodman's market reputation and straightforward design appeal to contractors managing replacement projects where upfront cost matters.

The 80% AFUE furnace with two-stage burner operation prevents the efficiency waste of single-stage units that run full-blast regardless of demand. Cooling capacity of 42,000 BTU delivers 14 SEER efficiency, which is solid mid-tier performance that won't command Energy Star certification but outperforms older 10-12 SEER systems. The multi-speed blower motor at 2000 CFM maximum airflow adapts to varying load conditions, reducing runtime waste. The 208/230V single-phase electrical requirement fits most residential panels with 22-35 amp breaker sizing.

Pros & Cons

Pros

Two-stage burner on 120,000 BTU furnace reduces short-cycling and improves comfort during mild weather
14 SEER cooling efficiency meets mid-range standards at competitive pricing tier
Multi-speed blower motor allows flexible airflow matching, optimizing performance across seasons
Horizontal configuration fits tight attic, basement, and crawlspace installations where vertical units won't fit
10-year warranty with online registration provides reasonable coverage for the price point
Low weight at 30 pounds simplifies horizontal mounting and reduces structural load concerns

Cons

80% AFUE is dated by today's standards, missing out on newer 95%+ high-efficiency models that pay back in 5-7 years
Single-stage condenser means the AC unit runs at full capacity constantly, increasing energy costs during partial-load conditions
73 dB noise level runs louder than premium units, noticeable during operation in quiet neighborhoods
Not Energy Star certified, indicating it doesn't meet current efficiency benchmarks for rebate eligibility
No mention of variable-speed compressor technology, limiting ability to modulate cooling demand

Who Should Buy

Best For

Budget-conscious homeowners and contractors tackling replacements in mild-to-moderate climates where the equipment will run part-time. This system suits properties with existing ductwork designed for standard airflow, where the horizontal configuration fits available space and installation complexity is a concern.

Consider Alternatives If

Anyone in high-heating regions like the upper Midwest or Northeast should look at 90%+ AFUE models, and homeowners seeking Energy Star rebates will miss qualification on this 80% unit.

3.5 Ton 14 SEER 80% AFUE 120,000 BTU Goodman Gas F

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Installation

Installation demands a metal exhaust flue and adequate refrigerant line sizing using 3/8 inch liquid and 7/8 inch suction lines with 3/8 inch insulation thickness. Horizontal mounting requires proper support to handle the 30-pound unit weight. PDF installation manuals and specification sheets guide technicians through ductwork connections and electrical setup. This configuration suits contractors comfortable with horizontal furnace installations in attics or basements.

Warranty & Reliability

Goodman provides 10-year parts warranty upon online registration, protecting against defects in the heat exchanger, blower motor, and compressor. This warranty is standard for mid-range units but shorter than some premium brands offering 12-15 years. Online registration is required, and coverage excludes normal wear items like filters and capacitors. Check local dealer policies since terms vary by region.

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	Metal
Furnace Efficiency / AFUE	80%
Blower Motor	Multi-Speed
Maximum CFM	2000
Configuration	Horizontal
Burner Stages	Two
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 is this 3.5 ton system listed as 5 tons in the specs? +

The 3.5 ton cooling capacity refers to the air conditioner, while the furnace heating capacity is separate at 120,000 BTU. The 5-ton tonnage reference in specs appears to be a data entry error or refers to a different capacity measurement. Clarify with your supplier before ordering to ensure the 3.5 ton cooling matches your load calculation.

Can I install this in an existing system designed for a different refrigerant? +

This unit accepts both R410A and R22 refrigerant, offering flexibility for replacements. However, verify your existing lineset compatibility before installation. If converting from R22 to R410A, you may need new refrigerant lines, larger capacity oil, and system flushing. Professional assessment is essential to avoid efficiency loss or equipment damage.

How much will the 80% AFUE furnace cost to operate compared to a 95% AFUE unit? +

An 80% AFUE furnace wastes 20% of fuel energy as exhaust, while 95% AFUE wastes only 5%. In heating-heavy climates, upgrading to 95% AFUE can save 3,000 to 5,000 dollars over 15 years. Run an ROI calculation for your region, factoring in installation costs and your natural gas rates to justify the upgrade.

Is 14 SEER good enough, or should I pay more for 16+ SEER? +

14 SEER is adequate for moderate climates but lags behind 16-18 SEER units in high-cooling regions like the South. Energy savings from higher SEER ratings typically exceed upgrade costs within 6-8 years in cooling-heavy areas. For mild climates, 14 SEER provides acceptable performance without premium pricing.

What does the 10-year warranty actually cover on this Goodman unit? +

The warranty covers compressor, heat exchanger, blower motor, and refrigerant circuit defects with online registration. It excludes routine maintenance, refrigerant top-ups, electrical components like capacitors, and labor costs. Read the full warranty document through Goodman's site before purchase to understand exclusions and claim procedures.

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