3 Ton 14 SEER 80% AFUE 100,000 BTU Goodman Gas Furnace and Air Conditioner System - Horizontal Review 2026

// Bottom Line

This is a solid mid-range choice for homeowners replacing older furnaces who want better efficiency without premium pricing. The two-stage burner and variable speed motor keep energy costs down while maintaining reliable heating through cold winters.

Review

Goodman's 3-ton horizontal furnace represents the middle ground in residential heating. This unit delivers 100,000 BTU of heating capacity and achieves 80% AFUE efficiency, meeting Energy Star standards without the premium cost of condensing models. The horizontal configuration makes it ideal for attic or crawlspace installations where traditional upflow furnaces don't fit. Weighing 30 pounds and measuring 21 by 21.125 by 26 inches, it offers a compact footprint while maintaining solid performance specs.

Performance-wise, the two-stage burner provides operational flexibility, ramping down during moderate heating demand to avoid short-cycling and unnecessary energy waste. The variable speed blower motor adjusts airflow up to 2,000 CFM based on heating needs, improving comfort and efficiency. Cooling capacity reaches 34,800 BTU with R410A or R22 refrigerant and a scroll compressor. At 73.5 dBA, noise levels are moderate, noticeable but not intrusive. The unit runs on 208-230V single phase, requiring 18.7 to 30 amp breakers.

Pros & Cons

Pros

80% AFUE rating beats standard 78% models and qualifies for Energy Star certification
Two-stage burner provides flexible heating and improved comfort during mild weather
Variable speed blower motor reduces energy waste and noise compared to single-speed designs
Horizontal configuration fits tight spaces where upflow units won't work
10-year warranty with online registration offers solid long-term protection
Handles both natural gas and propane for installation flexibility

Cons

80% AFUE lags behind 95%+ high-efficiency condensing furnaces by significant margin
Single-stage condenser limits cooling efficiency relative to dual-stage units
73.5 dBA noise level is audible and may be noticeable in quiet homes

Who Should Buy

Best For

Homeowners with horizontal furnace spaces (attics, crawlspaces) who need reliable heating without spending on high-efficiency condensing models. This works well for mild to moderate climates where the two-stage design prevents excess cycling.

Consider Alternatives If

Those in very cold climates needing maximum efficiency or homeowners willing to invest in 95%+ AFUE condensing furnaces that recover exhaust heat and deliver significantly lower operating costs.

3 Ton 14 SEER 80% AFUE 100,000 BTU Goodman Gas Fur

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Installation

Installation requires a metal flue for exhaust venting and standard refrigeration lines with 3/4 inch suction line insulation. Pre-charged linesets up to 50 feet accommodate various home layouts. Electrical connections use standard 208-230V service. Horizontal placement demands proper condensate drainage despite the 80% efficiency rating. Technicians should verify gas supply (natural gas or propane) and ensure adequate return air paths for optimal blower performance.

Warranty & Reliability

Goodman backs this unit with a 10-year parts warranty when you register online after purchase. This covers the compressor, heat exchanger, and components against manufacturing defects. Registration is straightforward through Goodman's website. The warranty does not cover labor, refrigerant, or wear items. For a mid-range furnace, a decade of coverage provides reasonable protection against unexpected failures.

Specifications

SKU	LS38783850
Brand/Manufacturer	Online Supply
Cooling BTU	34,800
Heating BTU	100,000
Refrigerant	R410A or R22
Electrical	208 / 230 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	73.5
Weight (in lbs)	30.000000
Feature	Spec
Airflow Direction	Upflow/Horizontal
Exhaust Flue Requirement	Metal
Furnace Efficiency / AFUE	80%
Blower Motor	Variable Speed
Maximum CFM	2000
Configuration	Horizontal
Burner Stages	Two
Fuel Type	Propane, Natural Gas
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.
Energy Star	Yes
SEER1 (Efficiency)	16
Condenser Stages	Single Stage
Compressor Type	Scroll
Liquid Valve Size	3/8"
Suction Valve Size	7/8"
Max Breaker Size	30 amps
Min. Breaker Size	18.7 amps
Tonnage	3.5 Ton
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 80% AFUE compare to other furnaces? +

80% AFUE means 80 cents of every heating dollar goes into your home while 20 cents escapes through the flue. Standard furnaces hit 78%, while premium condensing models reach 95%+. Over 15 years, the difference between 80% and 95% can exceed $2,000 in fuel savings, depending on climate and usage.

Can this horizontal furnace fit my attic space? +

At 21 by 21.125 by 26 inches, it's compact enough for most attics and crawlspaces. Verify your space dimensions before ordering. You'll need clearance around the unit for proper airflow and maintenance access. Metal flue venting must reach outside safely without sharp bends.

What's the advantage of two-stage heating? +

Two-stage burners modulate output between high and low, preventing the constant on-off cycling of single-stage units. This reduces energy waste during mild weather, improves comfort, and extends component lifespan. During harsh winter days, it still delivers full 100,000 BTU capacity.

How does this compare to a condensing furnace? +

Condensing furnaces (95% AFUE) extract additional heat from exhaust gases, costing $1,500 more upfront but saving $100-150 annually in fuel. This Goodman suits homeowners prioritizing affordability and decent efficiency over maximum savings. Choose condensing if you plan 20+ year ownership in cold climates.

Is the 10-year warranty transferable? +

Goodman's warranty applies to the original registered owner. Transferability to subsequent homeowners typically requires Goodman approval. Verify transfer terms before relying on warranty coverage as a selling point if you plan to sell within ten years.

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