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

// Bottom Line

This 5-ton Goodman system suits homeowners in moderate climates who prioritize heating efficiency and want to avoid high-end pricing. The 96% AFUE furnace with two-stage burners delivers consistent comfort, while the variable-speed ECM blower keeps energy costs down year-round.

Review

Goodman has built a solid reputation for delivering reliable HVAC equipment at reasonable price points, and this 5-ton downflow system exemplifies that philosophy. The unit combines a 100,000 BTU furnace with a 54,000 BTU air conditioner in a compact 30-by-21-by-21-inch footprint, making it suitable for basements, attics, and utility closets. Online Supply backs the system with a 10-year warranty and Energy Star certification, positioning it as a practical choice for contractors and homeowners balancing performance with budget constraints.

The furnace reaches 96% AFUE, which means only 4% of fuel energy escapes as waste, translating to lower heating bills over the unit's lifespan. The two-stage burner fine-tunes output to match demand, reducing temperature swings. The variable-speed ECM blower adjusts CFM from near-zero to 2,000 CFM, moderating electricity consumption during part-load operation. The air conditioner delivers SEER 16 cooling and 54,000 BTU capacity, acceptable for moderate climates but not competitive with 18-20 SEER systems gaining market share.

Pros & Cons

Pros

96% AFUE furnace efficiency reduces heating fuel costs significantly compared to 80-90% models
Variable-speed ECM blower motor automatically adjusts airflow, improving comfort and reducing electricity use
Two-stage burner operation provides better temperature stability than single-stage units
Energy Star certified system qualifies for utility rebates in many regions
PVC exhaust flue compatibility simplifies installation in older homes without masonry chimneys
10-year warranty with online registration covers compressor and major components

Cons

SEER 16 rating trails premium competitors offering SEER 18-20 systems with better cooling efficiency
73 dBA noise level is moderately loud for some residential settings, especially at night
Single-stage condenser limits cooling precision compared to two-stage or variable-capacity units
Requires 208/230V single-phase power, limiting compatibility in some rural or older electrical installations

Who Should Buy

Best For

Homeowners in the Midwest and upper South who run furnaces 4-6 months yearly and value heating efficiency over premium cooling performance. Contractors installing budget-conscious residential replacements where existing ductwork suits downflow configuration.

Consider Alternatives If

Buyers in hot climates needing aggressive summer cooling, those seeking ultra-high efficiency systems exceeding SEER 18, or installers working with properties lacking 208/230V electrical service.

5 Ton 15 SEER 96% AFUE 100,000 BTU Goodman Gas Fur

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Installation

This downflow configuration requires vertical or horizontal ductwork beneath the unit, common in basement or attic installations. PVC exhaust piping simplifies venting through exterior walls without expensive chimney modifications. Technicians need to verify existing 208/230V single-phase power availability and confirm ductwork handles 2,000 CFM maximum airflow. The 30-pound furnace component is portable for one-person installation, though complete system assembly typically requires two installers.

Warranty & Reliability

Online Supply provides 10 years of parts coverage upon online registration, covering the compressor, heat exchanger, blower motor, and control board. Registration is mandatory to activate full protection; unregistered units default to shorter coverage. This warranty is middle-of-road for the industry. Homeowners should retain documentation and proof of professional installation to validate claims.

Specifications

SKU	LS38783850
Brand/Manufacturer	Online Supply
Cooling BTU	54,000
Heating BTU	100,000
Refrigerant	R410A or R22
Electrical	208 / 230 V. 1 Phase 60 Hz
Warranty	10 Years with Online Registration
Decibel Level (dBA)	73
Weight (in lbs)	30.000000
Feature	Spec
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
Energy Star	Yes
Burner Stages	Two
Fuel Type	Propane, Natural Gas
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.
SEER1 (Efficiency)	16
Condenser Stages	Single Stage
Compressor Type	Scroll
Liquid Valve Size	3/8"
Suction Valve Size	7/8"
Max Breaker Size	50 amps
Min. Breaker Size	29.6 amps
Tonnage	5 Ton
Liquid Line	3/8"
Suction Line	7/8"
Style	A-Coil
Suction Line Insulation Thickness	3/4"
Length	50 feet

Frequently Asked Questions

What's the real difference between 96% AFUE and the 80% furnaces my neighbor has? +

At 96% AFUE, only 4% of your fuel escapes as waste versus 20% with an 80% unit. Over 20 years, that saves roughly 15,000 therms of natural gas or significant propane costs, depending on usage and local rates. The higher upfront cost pays back through lower heating bills.

Can I install this in my attic, or does downflow only work in basements? +

Downflow works in both locations. In attics, ductwork runs downward through walls and floors to supply rooms below. Ensure proper PVC exhaust venting through an exterior wall and verify your attic can support the 30-pound furnace plus ductwork weight without structural issues.

Is SEER 16 enough cooling for hot summers, or should I upgrade? +

SEER 16 handles mild to moderate cooling demands effectively. If summer temperatures exceed 95°F regularly or you live in high-humidity regions, consider SEER 18-20 units with two-stage compressors for superior dehumidification and part-load efficiency.

How does the variable-speed blower actually save money compared to single-speed models? +

Single-speed blowers run at full 2,000 CFM whenever heating or cooling activates, wasting electricity during mild weather. This Goodman's ECM motor ramps to 500-1,000 CFM on part-load days, cutting blower electricity use by 30-50% annually while improving comfort consistency.

What happens to my warranty if I don't register online within 30 days? +

Non-registered units default to a shorter warranty period, typically 5-7 years instead of 10. Registration is free and takes five minutes. Keep the AHRI certificate and installation paperwork as proof for any future claims.

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