3.5 Ton 15 SEER 97% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Upflow Review 2026

// Bottom Line

This is an excellent choice for homeowners upgrading older systems or contractors building efficient retrofit packages in residential applications. The 97% AFUE furnace paired with a 3.5-ton AC unit delivers solid year-round comfort with meaningful energy savings and reliable modulating burner technology.

Review

Goodman's 3.5-ton combo system positions itself as a practical middle ground in the residential HVAC market. It pairs a modulating furnace delivering 120,000 BTU heating output with a 42,000 BTU cooling capacity AC unit. This upflow configuration suits most basement or utility closet installations. The system carries Goodman's reputation for dependable performance at accessible pricing, making it popular with contractors stocking standard residential replacement units.

The furnace achieves 97% AFUE efficiency, meaning 97 cents of every fuel dollar converts to usable heat, drastically outperforming older 80% models still operating in many homes. The modulating burner continuously adjusts flame intensity rather than cycling fully on and off, reducing temperature swings and short-cycling wear. The variable-speed ECM blower motor ramps down during mild weather, cutting parasitic electrical draw. SEER1 rating of 16 on the cooling side provides solid efficiency for mid-tier AC performance, though single-stage operation limits modulation.

Pros & Cons

Pros

97% AFUE furnace efficiency captures nearly all fuel energy, reducing heating costs versus standard 80-90% units
Modulating burner adjusts heat output continuously rather than cycling on/off, improving comfort and consistency
Variable-speed ECM blower motor runs at lower speeds during mild weather, cutting electrical consumption
ENERGY STAR certified system qualifies for utility rebates that offset equipment cost
PVC flue venting simplifies installation compared to traditional metal venting requirements
10-year warranty with online registration covers parts and compressor protection

Cons

SEER1 rating of 16 is strong but not class-leading, older specs list 15 SEER in title versus 16 in data
5-ton capacity mismatch in specs conflicts with advertised 3.5-ton system, creating confusion on cooling output
Single-stage condenser cannot modulate cooling, limiting efficiency matching to furnace capabilities
73 dB noise level exceeds some whisper-quiet competitors, noticeable during operation

Who Should Buy

Best For

Homeowners in moderate climates needing balanced heating and cooling efficiency, and contractors building reliable mid-tier systems for residential retrofit or new construction. This system rewards users with consistent comfort and lower utility bills without premium pricing.

Consider Alternatives If

Buyers seeking cutting-edge two-stage cooling or those in regions with extreme heating demands who need 98%+ AFUE units should explore premium Goodman or competitor options.

3.5 Ton 15 SEER 97% AFUE 120,000 BTU Goodman Gas F

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Installation

This upflow unit fits standard equipment closets at 30 inches tall by 24.5 inches wide. Right-side flue placement allows flexible venting with plastic PVC pipe, eliminating expensive masonry or metal ductwork costs. The system requires 208/230V single-phase 60Hz power with breaker sizing between 23.5 and 40 amps. Most installations complete in one day with standard refrigerant lines, suction insulation, and standard gas piping.

Warranty & Reliability

Online Supply backs this system with a 10-year parts and compressor warranty activated through online registration. Coverage is straightforward with no hidden exclusions typical of budget equipment. The registration process takes minutes and ensures claims processing without documentation hassles, standard practice in today's market.

Specifications

SKU	LS381183850
Brand/Manufacturer	Online Supply
Cooling BTU	42,000
Heating BTU	120,000
Refrigerant	R410A
Electrical	208 / 230 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	73
Weight (in lbs)	48.000000
Feature	Spec
AHRI Certificate Number	7424268
Airflow Direction	Upflow/Horizontal
Exhaust Flue Requirement	Plastic / PVC
Product Features	Rebate Available
Furnace Efficiency / AFUE	97%
Blower Motor	Variable Speed - ECM
Maximum CFM	2000
Configuration	Upflow / Downflow
Flue Location	Right
Energy Star	Yes
Burner Stages	Modulating
Fuel Type	Propane, Natural Gas
Height	30"
Width	24.5"
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.
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
Liquid Line	3/8"
Suction Line	1 1/8"
Style	A-Coil
Suction Line Insulation Thickness	1/2"
Length	50 feet

Frequently Asked Questions

What does 97% AFUE actually save me compared to my old 80% furnace? +

A 17-percentage-point efficiency gain translates to roughly 20% lower heating costs annually. For homes burning $1,000 yearly in heating fuel, expect savings around $200. Over the system's 15-20 year lifespan, cumulative savings exceed $3,000 to $4,000 before accounting for fuel price increases.

Does this upflow configuration work in my basement installation? +

Yes, the 30-inch height and upflow design suit basements perfectly. The right-side flue venting through plastic PVC accommodates basement walls. Standard 3/8-inch liquid and 1-1/8-inch suction lines connect easily to outdoor condenser units, and the 2000 maximum CFM blower handles typical residential ductwork.

Why is the cooling capacity only 42,000 BTU for a 3.5-ton unit? +

The advertised tonnage appears inconsistent with actual specifications, which list 5-ton capacity. One ton equals 12,000 BTU, so 3.5 tons should be 42,000 BTU. The specs confirm 42,000 BTU cooling output, making this effectively a properly sized 3.5-ton system despite the conflicting tonnage notation in some documentation.

How does modulating burner technology compare to standard on-off burners? +

Modulating burners match heating output to actual demand, reducing overshooting and temperature swings. Standard burners run at full capacity then shut off completely, cycling frequently and creating temperature fluctuations. Modulating systems provide steadier comfort, reduce wear on components, and improve efficiency by avoiding excess heating waste.

What does the 10-year warranty actually cover? +

Coverage includes parts and compressor defects when you register online. Labor costs, refrigerant recharges, and routine maintenance aren't covered. The warranty protects against manufacturing defects but excludes installer or homeowner errors, standard industry practice.

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