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

// Bottom Line

This Goodman system works best for budget-conscious homeowners upgrading from older equipment who want solid efficiency without premium pricing. The 96% AFUE furnace and 18 SEER1 condenser deliver measurable energy savings while the two-stage design reduces runtime noise at 71 dB.

Review

Goodman has built a reputation for delivering dependable HVAC equipment at accessible pricing, and this 3-ton downflow system reinforces that position. At $736, the SKU LS38783850 lands squarely in the budget-to-mid-range category without sacrificing core efficiency metrics. The combination of a 96% AFUE furnace paired with an 18 SEER1 condenser makes this a genuine option for homeowners tired of utility bills climbing year over year. Online Supply backs the system with a 10-year warranty on parts.

The numbers justify the efficiency claims. The furnace delivers 80,000 BTU of heating output with two-stage burner control, while the condenser provides 35,000 BTU of cooling capacity. The variable-speed ECM blower motor dynamically adjusts between zero and 1,600 CFM, preventing the constant full-speed operation that plagues single-speed systems. Operating at 71 dB, this two-stage scroll compressor setup runs noticeably quieter than comparable single-stage units, a real benefit during evening cooling cycles.

Pros & Cons

Pros

96% AFUE furnace efficiency qualifies for many utility rebates, lowering actual installed cost
18 SEER1 rating on the condenser exceeds the product title claim of 17 SEER, providing better cooling efficiency
Two-stage burner and compressor reduce short-cycling and unnecessary runtime, extending equipment lifespan
Variable-speed ECM blower motor adjusts airflow between 0-1600 CFM based on demand, improving comfort and efficiency
PVC exhaust flue compatibility simplifies installation compared to metal vent requirements on older furnaces

Cons

Spec sheet lists both R410A and R22 refrigerant compatibility, but R22 is being phased out and harder to service
3.5 ton rating slightly oversizes the system for many three-ton applications, which may reduce efficiency in mild weather
10-year warranty requires online registration, adding a step that some homeowners forget and forfeit coverage

Who Should Buy

Best For

Homeowners replacing 15+ year old systems in moderate climates who prioritize operating cost savings over premium features. Contractors stocking mid-range equipment for residential new construction and replacements will appreciate the price point and Energy Star certification.

Consider Alternatives If

Anyone needing 80,000+ BTU heating capacity should look at larger systems, and buyers in extremely cold climates may want higher AFUE ratings or dual-fuel backup options.

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

$736

Buy at HVACDirect →

Installation

Installation requires standard residential electrical service (115V, 1-phase, 60 Hz) with breaker capacity between 21.3 and 35 amps. The downflow configuration suits basements and attics with adequate clearance. Refrigerant line sizing calls for 3/8 inch liquid and 7/8 inch suction lines with 3/4 inch insulation. PVC exhaust venting is required. Most contractors complete installation in 4-6 hours with standard tools.

Warranty & Reliability

Online Supply provides 10 years of parts coverage after online registration, a solid baseline for this price tier. The Goodman evaporator coil carries its own warranty document. Coverage excludes labor, refrigerant, and damage from improper installation or maintenance. Registration is required to activate coverage, so homeowners should complete this immediately after installation.

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	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
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

Why does the product title say 17 SEER but the specs list 18 SEER1? +

SEER1 is a newer, more stringent efficiency metric replacing the older SEER standard. The condenser achieves 18 SEER1, which is actually stronger than the 17 SEER mentioned in marketing copy. You're getting better-than-advertised cooling efficiency. Always verify SEER1 ratings in modern systems for apples-to-apples comparison.

Can this system work with my existing ductwork in a 1,200 square foot home? +

At 3.5 tons with 1,600 CFM maximum airflow, this system suits homes up to roughly 1,400 square feet. Verify your ductwork can handle 1,600 CFM without exceeding 0.1 inches of static pressure. Have an HVAC contractor perform a Manual D load calculation to confirm proper sizing and duct adequacy before purchase.

Does the 96% AFUE furnace really save that much compared to an 80% system? +

Yes. A 96% furnace wastes only 4 cents of every heating dollar, versus 20 cents on an 80% model. Heating costs 40-60% of annual utility bills in cold climates. Over 15 years, the 96% system saves $1,500 to $3,000 in fuel costs, easily offsetting the modest equipment premium.

How does this Goodman compare to higher-end brands like Lennox or Carrier? +

This Goodman delivers comparable efficiency metrics at 40-50% lower cost. Premium brands add extended warranties, quieter compressors, and advanced controls. For budget-conscious buyers, Goodman's two-stage design and variable-speed blower provide 85% of the performance at 55% of the price.

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

Coverage is forfeited without registration. Contact Online Supply with your serial number and date of installation within 30 days of startup. Many contractors register systems on behalf of customers, but verify this happened before leaving the job site.

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