3 Ton 17 SEER 96% AFUE 80,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow Review 2026

// Bottom Line

This Goodman combo system works best for homeowners replacing aging equipment in moderate climates who prioritize upfront savings without sacrificing efficiency ratings. At $504, you're getting legitimate 96% AFUE heating and 18 SEER cooling performance typically found in systems costing significantly more.

Review

Goodman's downflow combo system at $504 represents the sweet spot between budget constraints and actual performance. This isn't a stripped-down unit with inflated specs, it's a legitimate dual-stage furnace paired with a two-stage compressor condenser. Online Supply positions this as a value play for contractors servicing rental properties and budget-conscious homeowners who understand that efficiency ratings matter more than brand cachet.

The 96% AFUE furnace with two-stage burners captures nearly all combustible energy, translating to measurable heating cost reductions. Cooling performance delivers 18 SEER2 and 35,000 BTU capacity through a scroll compressor running at 71 dB, quiet enough for basements. The variable-speed ECM blower adjusts between 0-1600 CFM automatically, avoiding the constant on-off cycling that wastes energy in single-stage systems. R410A refrigerant ensures modern refrigerant compliance without future phase-out concerns.

Pros & Cons

Pros

96% AFUE furnace efficiency with two-stage burners minimizes heating costs during winter months
18 SEER2 cooling rating exceeds ENERGY STAR requirements and qualifies for utility rebates
Two-stage scroll compressor reduces runtime noise to 71 dB and improves part-load efficiency
Variable-speed ECM blower motor adjusts CFM up to 1600 based on actual heating/cooling demand
PVC exhaust compatibility simplifies venting in retrofit applications where metal flues are problematic
10-year warranty with online registration provides meaningful coverage at this price tier

Cons

3.5-ton capacity limits this to homes under 1,400 square feet, making oversizing impossible for larger properties
Downflow configuration restricts placement to basements or attics only, incompatible with crawlspace installations
Online Supply brand offers limited contractor support compared to major manufacturers like Carrier or Lennox

Who Should Buy

Best For

This system suits homeowners in mild-to-moderate climates replacing 10-15 year old split systems on tight budgets. It's particularly attractive for small to mid-sized homes where you want legitimate efficiency without paying premium brand pricing.

Consider Alternatives If

Skip this if you have a home over 1,400 square feet, need a side-mount configuration, or live in extreme climates where variable-stage operation becomes inefficient.

3 Ton 17 SEER 96% AFUE 80,000 BTU Goodman Gas Furn

$504

Buy at HVACDirect →

Installation

Downflow configuration requires basement or attic mounting with gravity assistance. The 3/8 inch liquid and 7/8 inch suction lines need proper insulation and pitch support, though the included 50-foot suction line insulation simplifies that work. Single-phase 115V input at 21.3-35 amp range fits standard residential wiring without electrical upgrades. PVC exhaust venting eliminates masonry flue requirements, reducing installation complexity significantly.

Warranty & Reliability

The 10-year parts warranty activates only with online registration, a standard practice that protects both manufacturer and buyer. Coverage includes the scroll compressor, furnace heat exchanger, and condenser coil. This exceeds the 5-year standard on many budget systems but trails the 12-year coverage from premium brands, reflecting the price difference appropriately.

Specifications

SKU	LS38783850
Brand/Manufacturer	Online Supply
Cooling BTU	35,000
Heating BTU	80,000
Refrigerant	R410A or R22
Electrical	115 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	71
Weight (in lbs)	30.000000
Feature	Spec
Product Features	Rebate Available
Energy Star	Yes
SEER1 (Efficiency)	18
Condenser Stages	Two Stage
Compressor Type	Scroll
Liquid Valve Size	3/8"
Suction Valve Size	3/4"
Max Breaker Size	35 amps
Min. Breaker Size	21.3 amps
Tonnage	3.5 Ton
Valve Type	Sweat
Height	30"
Width	24.5"
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
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	7/8"
Style	A-Coil
Suction Line Insulation Thickness	3/4"
Length	50 feet

Frequently Asked Questions

What's the actual difference between 17 SEER and 18 SEER2 ratings on this unit? +

SEER2 uses stricter testing conditions reflecting real-world performance better than legacy SEER ratings. This unit's 18 SEER2 represents roughly equivalent cooling to a 21 SEER system under old standards. The two-stage compressor maintains efficiency during partial-load conditions, delivering consistent performance even on mild days.

Can I install this in an upflow orientation, or is it locked to downflow? +

The specs list configuration as both upflow and downflow capable, but purchasing details specify downflow. Contact Online Supply before purchase to confirm upflow availability. A-coil design works in either orientation, though existing ductwork may prevent conversion after installation.

How does 96% AFUE compare to my current furnace efficiency? +

If your furnace is over 15 years old, it likely operates at 78-82% AFUE, meaning 14-18% of fuel costs disappear as waste heat. Upgrading to 96% AFUE saves approximately 15-20% on annual heating costs depending on local gas prices and climate zone.

Is this better than a single-stage Goodman system that costs less? +

Two-stage burners and compressors reduce short-cycling and runtime by operating at 60% capacity during mild weather. This improves comfort consistency and extends equipment lifespan significantly compared to single-stage units that cycle constantly between full on and off states.

What happens to my warranty if I don't register online? +

Registration is required to activate the 10-year coverage. Without it, you'll lose warranty protection entirely. Registration takes five minutes on Goodman's website and requires your serial number and purchase receipt.

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