3 Ton 17 SEER 96% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow Review 2026

// Bottom Line

This system makes sense for homeowners replacing aging equipment who want genuine efficiency gains without premium pricing. The 96% AFUE furnace and two-stage compressor deliver measurable savings on both heating and cooling bills, especially in moderate climates where the system cycles regularly.

Review

The Goodman 3-ton combined gas furnace and air conditioner system sits in the sweet spot between budget units and premium equipment. At $3,640, it delivers legitimate high-efficiency specs without the 5-figure price tags of modulating or variable-stage competitors. Online Supply packages this system with reasonable accessibility, AHRI certification for contractor confidence, and Energy Star qualification. The downflow configuration works for basement installations, crawlspace applications, or horizontal attic placement depending on ductwork layout.

Real performance numbers tell the story here. The 120,000 BTU furnace operates at 96% AFUE, meaning 96 cents of every dollar spent on fuel converts to usable heat. The 35,000 BTU cooling capacity pairs with an 18 SEER2 rating, indicating strong seasonal efficiency across varying temperature conditions. Two-stage operation on both heating and cooling prevents the efficiency penalties of constant full-capacity running. The variable-speed ECM blower motor automatically adjusts to deliver optimal airflow without excessive electricity draw, which adds up over 8,760 annual hours of operation.

Pros & Cons

Pros

96% AFUE furnace exceeds most entry-level units by 10-15 percentage points, reducing annual heating costs significantly
18 SEER2 rating confirms strong cooling efficiency, paired with variable-speed ECM blower for reduced runtime waste
Two-stage heating and cooling prevents short-cycling and unnecessary full-capacity operation on mild days
3.5-ton capacity handles 3-ton loads with efficiency headroom, avoiding oversized equipment penalties
PVC flue compatible design simplifies installation in homes with restrictive chimney situations
Scroll compressor offers proven reliability record with lower failure rates than rotary alternatives

Cons

Spec sheet lists contradictory tonnage (3-ton in title, 3.5-ton in specs), creating confusion during ordering
10-year warranty requires online registration, which some homeowners may overlook or forget to complete
71 dB operating level acceptable but not whisper-quiet compared to premium variable-speed competitors

Who Should Buy

Best For

Homeowners in moderate to cold climates replacing 15+ year old furnaces will see immediate energy bill reductions. Contractors building value-conscious packages appreciate the AHRI certification and straightforward installation profile.

Consider Alternatives If

Ultra-quiet operation seekers or homes with severely undersized electrical service (under 21.3 amps available) should explore alternatives.

3 Ton 17 SEER 96% AFUE 120,000 BTU Goodman Gas Fur

$3640

Buy at HVACDirect →

Installation

This system requires standard refrigerant lines (3/8-inch liquid, 7/8-inch suction with 3/4-inch insulation) and basic electrical work at 115V single-phase 60Hz. The 21.3 to 35-amp breaker range fits most residential panels. PVC flue capability simplifies venting compared to older masonry chimney requirements. Downflow orientation needs adequate space below the unit for condensate drainage and blower intake. Licensed HVAC installer strongly recommended for proper evacuation, charging, and startup.

Warranty & Reliability

The 10-year comprehensive warranty covers parts and labor when you complete online registration after installation. This timeline protects against early compressor failures and component defects but excludes wear items like blower motors and capacitors after 5 years. Registration immediately after commissioning ensures the coverage window starts correctly and prevents documentation delays if problems emerge.

Specifications

SKU	LS38783850
Brand/Manufacturer	Online Supply
Cooling BTU	35,000
Heating BTU	120,000
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	7368845
Airflow Direction	Downflow/Horizontal
Exhaust Flue Requirement	Plastic / PVC
Furnace Efficiency / AFUE	96%
Blower Motor	Variable Speed - ECM
Maximum CFM	2000
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 spec sheet say both 3-ton and 3.5-ton? +

The system is rated 3.5-ton capacity but marketed as suitable for 3-ton applications, providing 500-pound capacity headroom. This prevents oversizing penalties while handling peak summer loads without strain. Verify cooling load calculations before ordering to ensure proper sizing for your home.

Can I install this myself or upgrade from my existing system? +

Federal refrigerant handling regulations require EPA-certified technicians for any work touching refrigerant lines. Most homeowners can handle electrical connections and ductwork modifications, but compressor evacuation, charging, and pressure testing demand professional licensing. Labor costs typically run $1,500 to $2,500 depending on existing infrastructure condition.

How much will this actually save me compared to a basic 13 SEER unit? +

The 18 SEER2 versus 13 SEER represents roughly 30-35% better cooling efficiency. On heating, 96% AFUE versus 80% AFUE (typical for older units) recovers an additional 16% of fuel energy. Annual savings in moderate climates range from $400 to $800 depending on local electricity and gas rates.

How does this compare to higher-SEER variable-refrigerant models? +

Premium systems reach 20+ SEER2 but cost $5,500 to $7,500 installed. This Goodman delivers 85-90% of that efficiency at 60-70% of the price. The two-stage approach offers better part-load performance than single-stage units without the complexity and cost of fully variable systems.

Is the 10-year warranty actually useful if parts fail? +

Yes, provided you register online immediately after installation. The warranty covers compressor replacement and refrigerant leaks, which are the most expensive failures. Exclusions apply to wear items after 5 years, but core components remain covered through year 10.

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