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

// Bottom Line

This Goodman 3.5-ton system excels for homeowners seeking strong heating and cooling efficiency without premium pricing. The 96% AFUE furnace and 16 SEER1 condenser make it ideal for mixed climates where both heating and cooling demand significant use.

Review

Goodman's dual-fuel system pairs a 96% AFUE furnace with a 16 SEER1 air conditioner in a downflow configuration rated for propane or natural gas. This SKU LS381183850 targets contractors and homeowners balancing heating and cooling needs without stretching budgets. The combination earns Energy Star certification and includes a scroll compressor with two-stage burner technology, positioning it as a mid-tier performer in the residential HVAC market.

Heating output reaches 80,000 BTU across two burner stages, while cooling delivers 42,000 BTU in single-stage operation. The variable-speed ECM blower pushes up to 1,600 CFM and maintains a quiet 73 dB sound level. Electrical requirements are modest at 115V, 1-phase, 60 Hz with a 40-amp maximum breaker. These specs deliver solid efficiency without exotic refrigerant demands, using standard R410A or R22.

Pros & Cons

Pros

96% AFUE furnace means you recover nearly all heating energy, translating to lower winter bills
16 SEER1 rating on the condenser exceeds the 3.5-ton baseline and qualifies for Energy Star
Variable-speed ECM blower motor adapts airflow to demand, improving comfort and reducing runtime noise to 73 dB
Two-stage burner allows the furnace to run at partial capacity most of the time, extending equipment life
10-year warranty with online registration covers both heating and cooling components

Cons

Spec sheet lists both 3.5-ton and 5-ton tonnage, creating confusion about actual cooling capacity
42,000 BTU cooling output sits below typical 3.5-ton systems, which usually deliver 42,000 BTU, but indoor/outdoor matching matters
Single-stage condenser compressor cannot modulate, so it cycles on and off rather than varying capacity

Who Should Buy

Best For

Contractors installing split systems in homes with moderate heating and cooling demands, or homeowners in climates where winter heating drives equipment selection. This pairing works well in regions with 4,000+ heating degree days and moderate summer cooling needs.

Consider Alternatives If

Anyone in hot climates needing variable-capacity cooling should consider a two-stage compressor instead. Homeowners seeking modulating heat also need a modulating condenser matched to this furnace.

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

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Installation

Downflow/horizontal orientation suits basements and attic spaces with headroom constraints. The system uses PVC exhaust flue, simplifying venting compared to metal options. Refrigerant lines require 3/8 inch liquid and 1 1/8 inch suction piping with 1/2 inch insulation, rated for 50 feet runs. Compact dimensions (30 inches tall, 21 by 21 inches deep) fit tight utility closets.

Warranty & Reliability

Ten-year parts coverage activates upon online registration, protecting both furnace and condenser against defects. This warranty spans compressor, heat exchanger, and refrigerant circuits. Online registration is required, so buyers must complete this step within the activation window to secure full protection.

Specifications

SKU	LS381183850
Brand/Manufacturer	Online Supply
Cooling BTU	42,000
Heating BTU	80,000
Refrigerant	R410A or R22
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	CAPF Installation Manual CAPF 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

Is this truly 3.5 tons or 5 tons? +

The spec sheet shows conflicting tonnage ratings. The 42,000 BTU cooling capacity aligns with 3.5-ton systems, but the listing also references 5-ton specs. Contact the supplier for clarification before purchase to ensure indoor coil compatibility and proper system design.

Can this furnace work with an older air conditioner? +

Possibly, but matching matters. The furnace's 80,000 BTU heating and two-stage operation require compatible ductwork and controls. Most upgrades pair new furnaces with new condensers to ensure refrigerant type, airflow, and electrical alignment. Mixing old and new often voids warranties.

How does 16 SEER1 compare to typical air conditioners? +

16 SEER1 exceeds the federal minimum of 13 SEER for most regions and beats average 14 SEER equipment. However, single-stage compressors cannot modulate, so efficiency gains come from the blower and coil design rather than variable cooling capacity. Two-stage condensers typically achieve higher SEER ratings.

What's the difference between this Goodman and a Lennox or Carrier system? +

Goodman competes on price and simplicity. Lennox and Carrier often offer modulating compressors and higher SEER ratings, but cost significantly more. Goodman's two-stage furnace and variable-speed blower bridge the efficiency gap without premium pricing, making it popular with cost-conscious contractors.

Does the 10-year warranty cover labor? +

No, the warranty covers parts only. Labor, refrigerant, and ductwork modifications are the homeowner's responsibility. Contractor installation warranties vary, so confirm coverage details with your HVAC installer before signing.

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