3 Ton 17 SEER 97% AFUE 100,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow Review 2026

// Bottom Line

This system works best for homeowners replacing older equipment in homes with existing ductwork configured for downflow delivery. The 97% AFUE furnace paired with an 18 SEER2 condenser delivers genuine savings on both heating and cooling, and the $504 price tag makes it accessible for budget-conscious retrofits.

Review

This Goodman system represents a practical middle ground in the HVAC market, offering legitimate efficiency improvements at an entry price that appeals to budget-focused buyers and contractors managing retrofit jobs. The combination of 97% AFUE heating and 18 SEER2 cooling sits above typical mid-range equipment but below premium offerings. At $504 with a rebate available, it occupies competitive terrain where value meets performance without excessive cost. The downflow configuration limits versatility, but for homes already designed around this airflow pattern, the system delivers measurable returns on investment.

Performance specifications reveal a well-balanced design. The furnace produces 100,000 BTU of heat with modulating burner stages that vary output based on demand, reducing short-cycling and fuel waste. The 3.5 ton condenser handles 35,000 BTU cooling capacity with a two-stage scroll compressor, allowing partial load operation during mild weather. The variable-speed ECM blower adjusts to 2000 CFM maximum, matching output to actual heating and cooling requirements. These features work together to reduce energy consumption compared to fixed-speed systems, translating to lower utility bills over the equipment's lifespan.

Pros & Cons

Pros

97% AFUE heating efficiency means nearly all fuel converts to usable heat, reducing winter utility bills significantly
18 SEER2 cooling rating on the condenser exceeds the 17 SEER claimed for the system, indicating strong AC performance
Two-stage compressor with modulating burner allows the system to run at partial capacity during mild weather, cutting runtime and energy use
Variable-speed ECM blower motor adjusts CFM up to 2000 based on actual heating and cooling demand
PVC/plastic exhaust compatibility simplifies venting in retrofit applications where metal flues create clearance problems

Cons

3.5 ton capacity creates a 0.5 ton mismatch with the marketed 3 ton rating, requiring careful load calculation verification
71 dB noise level places this unit in the louder range for condenser operation, which matters in noise-sensitive neighborhoods
Downflow configuration limits installation flexibility to homes already set up for this airflow direction

Who Should Buy

Best For

Homeowners in moderate climates replacing 10+ year old furnace and AC systems who want efficiency gains without premium pricing. Contractors managing retrofit projects where downflow installation is already in place and budget constraints prevent higher-tier options.

Consider Alternatives If

Anyone needing upflow only configuration, homes in extremely cold climates requiring maximum BTU output, or buyers prioritizing whisper-quiet operation.

3 Ton 17 SEER 97% AFUE 100,000 BTU Goodman Gas Fur

$504

Buy at HVACDirect →

Installation

Installation requires standard 115V single-phase power with breaker sizing between 21.3 and 35 amps, fitting most residential electrical panels. The system uses sweat valve connections with 3/8 inch liquid and 7/8 inch suction lines, plus 3/4 inch suction line insulation. PVC exhaust venting simplifies installation in tight spaces where metal ducting won't fit. Downflow orientation means the coil and furnace stack vertically, requiring adequate ceiling clearance. Proper refrigerant line length and sizing matter significantly, so HVAC professionals should follow the CAPF Installation Manual closely.

Warranty & Reliability

A 10-year warranty covers equipment defects when you register online after installation. This extended coverage is typical for modern HVAC systems and provides genuine protection against compressor or heat exchanger failures. Online registration is mandatory to activate the full term, so save documentation and complete this step immediately after startup. Coverage excludes normal wear, refrigerant loss from leaks, or improper installation.

Specifications

SKU	LS38783850
Brand/Manufacturer	Online Supply
Cooling BTU	35,000
Heating BTU	100,000
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	7424272
Airflow Direction	Downflow/Horizontal
Exhaust Flue Requirement	Plastic / PVC
Furnace Efficiency / AFUE	97%
Blower Motor	Variable Speed - ECM
Maximum CFM	2000
Configuration	Upflow / Downflow
Burner Stages	Modulating
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 say 3 ton but the specs show 3.5 ton? +

The 3.5 ton rating refers to cooling capacity, while marketing emphasizes 3 ton for round-number appeal. The 35,000 BTU cooling output equals 3.5 tons of refrigeration. Verify your home's actual cooling load through a Manual J calculation before purchasing to ensure proper sizing. Oversizing wastes energy and reduces dehumidification.

Can this system work with my existing R22 equipment or must I switch to R410A? +

This unit accepts both R410A or R22 refrigerant, providing flexibility during retrofit work. However, R22 availability is phasing out due to EPA regulations, and pricing has become expensive. Most new installations use R410A going forward. Check what refrigerant your existing equipment uses before ordering to ensure compatibility.

How much will this system actually reduce my heating and cooling costs? +

A 97% AFUE furnace uses approximately 3% less fuel than an 94% AFUE unit, saving roughly 3% on heating bills. The 18 SEER2 rating delivers similar proportional savings versus 14 SEER equipment. Real savings depend on climate, usage patterns, and your current system's age and condition. Older equipment replaced will show more dramatic improvements than replacing relatively modern units.

How does this Goodman system compare to Lennox or Carrier at similar price points? +

Goodman and Lennox efficiency ratings are comparable at this price tier, with both offering 97% AFUE and high SEER options. Lennox typically prices higher but includes more refined controls. Carrier systems at this cost usually feature lower AFUE ratings. All three offer solid 10-year warranties. Choose based on local service availability, as technician support matters more than brand.

Is the 10-year warranty worth the registration effort? +

Yes. The extended coverage protects your major investment for a decade with minimal effort. Registration takes five minutes online and requires your serial number. Without registration, warranty reverts to a shorter term. This protection is valuable if compressor or heat exchanger failures occur after year five of operation.

Affiliate disclosure: IndustrialRank earns a commission on qualifying purchases at no extra cost to you. We only recommend products we have independently reviewed.