3.5 Ton 15 SEER 96% AFUE 80,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow Review 2026

// Bottom Line

This Goodman system is ideal for homeowners upgrading older furnaces and AC units who prioritize heating efficiency and want a complete matched pair. The 96% AFUE furnace with two-stage burners delivers substantial winter savings, while the 16 SEER2 air conditioner keeps cooling costs reasonable in moderate climates.

Review

Goodman equipment has earned respect among contractors for straightforward engineering and consistent performance. This 3.5-ton split system pairs a furnace with an air conditioner, both optimized for downflow applications common in basements and crawl spaces. The combination offers Energy Star certification and qualifies for utility rebates in most regions, making it financially attractive for homeowners prioritizing efficiency without premium pricing.

The furnace's 96% AFUE rating and 80,000 BTU capacity deliver efficient heating through a two-stage burner system that modulates flame output. The air conditioner produces 42,000 cooling BTU with a 16 SEER2 rating, surpassing the advertised 15 SEER specification. Variable-speed ECM blower reaches 1600 CFM maximum while optimizing distribution, and the scroll compressor uses R410A refrigerant with 40-amp service capacity at 115V single-phase.

Pros & Cons

Pros

96% AFUE furnace rating means minimal fuel waste and lower winter heating bills for gas heating homes
16 SEER2 condenser exceeds the 15 SEER specification, offering better cooling efficiency than baseline
Two-stage furnace burner adjusts output based on demand, improving comfort and reducing short-cycling
Variable-speed ECM blower motor fine-tunes airflow to 1600 CFM maximum, enhancing efficiency across seasons
Energy Star certified system qualifies for utility rebates that offset portion of installation costs

Cons

Spec sheet contains conflicting tonnage data, listing both 3.5 and 5 tons, creating confusion during sizing verification
73 dB noise level is moderately loud for a residential condenser, noticeable during operation in quiet neighborhoods
Single-stage cooling compressor cannot modulate capacity, reducing part-load efficiency compared to variable-capacity competitors

Who Should Buy

Best For

Homeowners in HVAC zones with cold winters and moderate summers who are replacing 15-20 year old split systems and want to maximize heating efficiency. Contractors seeking reliable Goodman equipment for value-conscious customers who prioritize AFUE ratings.

Consider Alternatives If

Buyers in hot climates where cooling dominates should consider variable-speed compressor systems, and those seeking ultra-quiet operation should evaluate alternatives below 70 dB.

3.5 Ton 15 SEER 96% AFUE 80,000 BTU Goodman Gas Fu

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Installation

This downflow unit requires plastic PVC exhaust venting and standard 3/8 inch liquid lines with 1/2 inch suction line insulation rated for 50-foot runs. Technicians need 23.5 to 40-amp electrical service, straightforward for most homes with existing dual-fuel infrastructure. A-coil design fits vertical configurations typical of basement installations, reducing custom ductwork complexity.

Warranty & Reliability

Goodman backs this system with 10-year coverage when registered online after installation. Warranty includes parts and compressor, though labor coverage varies by retailer. Online Supply's registration process is simple, protecting your investment through the critical first decade of operation when manufacturing defects are most likely to surface.

Specifications

SKU	LS381183850
Brand/Manufacturer	Online Supply
Cooling BTU	42,000
Heating BTU	80,000
Refrigerant	R410A
Electrical	115 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	73
Weight (in lbs)	48.000000
Feature	Spec
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	40 amps
Min. Breaker Size	23.5 amps
Tonnage	5 Ton
Height	30"
Width	21"
Depth	21"
Resources	CAPT Installation Manual CAPT 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.
AHRI Certificate Number	7368843
Airflow Direction	Downflow/Horizontal
Exhaust Flue Requirement	Plastic / PVC
Product Features	Rebate Available
Furnace Efficiency / AFUE	96%
Blower Motor	Variable Speed - ECM
Maximum CFM	1600
Configuration	Upflow / Downflow
Burner Stages	Two
Fuel Type	Propane, Natural Gas
Liquid Line	3/8"
Suction Line	1 1/8"
Style	A-Coil
Suction Line Insulation Thickness	1/2"
Length	50 feet

Frequently Asked Questions

Why does the spec sheet list both 3.5 and 5 tons? +

The product title claims 3.5 tons, but specifications show 5-ton cooling capacity. This discrepancy suggests either a catalog error or a unit size classification mismatch. Verify the actual cooling capacity (42,000 BTU) matches your home's cooling load before purchase to avoid undersizing or oversizing issues.

Can this furnace burn propane or only natural gas? +

The specifications list both propane and natural gas as fuel options, but most units ship configured for natural gas. Propane conversion requires a different orifice kit and regulator adjustment. Contact Online Supply before purchasing if you have propane service to confirm conversion availability and any additional costs involved.

How does 16 SEER2 compare to the advertised 15 SEER rating? +

SEER2 is the newer efficiency metric that replaced SEER, using tougher testing standards. The 16 SEER2 rating actually exceeds the advertised 15 SEER, meaning this unit performs better than described. However, direct SEER-to-SEER2 comparison is imprecise; expect roughly 20 percent lower efficiency when converting older ratings.

Is this system better than a high-SEER variable-speed unit? +

This single-stage compressor operates at full capacity whenever cooling is needed, while variable-speed systems modulate capacity. Variable systems excel in mild weather part-load operation, but this Goodman costs significantly less. Choose this system if budget matters more than maximizing efficiency during spring and fall shoulder seasons.

What does the 10-year warranty actually cover after registration? +

Coverage includes parts and compressor failure due to manufacturing defects. Labor, refrigerant recharge, and maintenance items are typically excluded. Registration is required within 30 days of installation, so complete this immediately after professional setup to activate full warranty protection.

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