3.5 Ton 15 SEER 96% AFUE 100,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow Review 2026

// Bottom Line

This 3.5-ton Goodman system excels for contractors and homeowners needing robust heating with solid cooling efficiency. The 96% AFUE furnace and variable-speed ECM blower deliver comfort and measurable energy savings in mixed climates.

Review

Goodman's gas furnace and air conditioner system targets the middle-market contractor and performance-conscious homeowner. The 3.5-ton capacity (though specs list 5 ton, creating labeling confusion) pairs a 96% AFUE furnace with a 16 SEER1 condenser in a downflow configuration suitable for basement installations. Online Supply markets this as an Energy Star-qualified option with rebate availability, positioning it against mid-tier competitors rather than budget equipment.

The heating side delivers 100,000 BTU across two burner stages, while cooling produces 42,000 BTU with a scroll compressor running single-stage. The variable-speed ECM blower motor reaches 2,000 CFM maximum and adjusts consumption based on demand, reducing idle energy waste. At 115V, 1-phase operation, it requires 23.5 to 40 amps, making it compatible with standard residential electrical service. These specs support reliable performance across diverse climates and load conditions.

Pros & Cons

Pros

96% AFUE furnace efficiency beats standard 80% units by significant margin on heating costs
16 SEER1 cooling rating with Energy Star certification covers both seasonal metrics well
Variable-speed ECM blower motor adjusts to demand, reducing runtime and electricity waste
Two-stage burner allows modulation for improved comfort and efficiency during partial-load operation
Flexible fuel compatibility with natural gas or propane supports diverse installation scenarios
10-year warranty with online registration provides solid long-term protection

Cons

Specs list conflicting tonnage (title says 3.5 ton but specs show 5 ton, creating confusion
73 dB noise level runs slightly louder than premium single-stage competitors
Single-stage cooling compressor lacks modulation that two-stage units provide for quieter operation

Who Should Buy

Best For

Contractors building systems for cold climates where furnace efficiency directly impacts ROI, and homeowners upgrading from aging 80% AFUE units who can recoup costs through heating savings. The two-stage burner and variable blower are particularly valuable in areas with long heating seasons.

Consider Alternatives If

Buyers seeking the quietest possible operation should explore two-stage compressor models, and those in mild climates may find the high AFUE investment unnecessary compared to lower-efficiency alternatives.

3.5 Ton 15 SEER 96% AFUE 100,000 BTU Goodman Gas F

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Installation

This downflow unit fits standard basement applications with 30-inch height fitting most crawlspaces. It requires PVC/plastic exhaust venting per modern codes and uses standard refrigerant line sizes: 3/8 inch liquid and 7/8 inch suction with 1/2 inch insulation. Pre-charged to 50 feet of lineset length, installers can extend runs with proper recovery and recharge procedures. Single-phase 115V power simplifies electrical hookup significantly.

Warranty & Reliability

The 10-year warranty with online registration provides coverage on parts and labor during the protection period, standard for mid-tier Goodman equipment. Registration is required to activate the full term, so buyers must complete paperwork promptly. This term compares favorably to budget alternatives but trails some premium brands offering 12-year or lifetime coverage.

Specifications

SKU	LS381183850
Brand/Manufacturer	Online Supply
Cooling BTU	42,000
Heating BTU	100,000
Refrigerant	R410A or R22
Electrical	115 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	73
Weight (in lbs)	48.000000
Feature	Spec
Energy Star	Yes
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
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	7368844
Airflow Direction	Downflow/Horizontal
Exhaust Flue Requirement	Plastic / PVC
Product Features	Rebate Available
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	1 1/8"
Style	A-Coil
Suction Line Insulation Thickness	1/2"
Length	50 feet

Frequently Asked Questions

What is the actual tonnage of this unit, given conflicting specs? +

The title states 3.5 tons, but specifications list 5 tons. With 42,000 BTU cooling capacity, this calculates to 3.5 tons (12,000 BTU per ton). Verify with Online Supply before purchase, as specification errors can affect system sizing and warranty compliance.

Can this system use both R410A and R22 refrigerant? +

The specs mention both refrigerants, but modern Goodman units ship pre-charged with R410A. R22 is obsolete and illegal for new installations. Confirm refrigerant type with your installer before ordering, as equipment certification depends on correct charge.

How much can I expect to save on heating with 96% AFUE versus my old 80% furnace? +

A 96% AFUE unit converts 16% more input energy to usable heat than 80% models. On a $1,200 annual heating bill, you save approximately $180 to $240 annually depending on fuel prices and thermostat settings. Payback typically occurs within 5-7 years.

Is the 73 dB noise level problematic for residential use? +

At 73 dB, the unit runs roughly as loud as a vacuum cleaner during operation. This falls within acceptable residential range but may be audible from adjacent rooms. Two-stage compressor systems operate 3-5 dB quieter if noise is a priority.

What does the 10-year warranty actually cover? +

Parts and labor coverage applies to manufacturing defects during the 10-year period with online registration required. Routine maintenance, refrigerant loss from leaks, and wear items like capacitors are typically excluded. Read the full warranty document before installation.

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