Independent Review · Updated June 2026

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

Budget-friendly 3-ton combo with solid 96% AFUE and 18 SEER1 efficiency

8.2
IndustrialRank Score
Efficiency
8.5
Reliability
7.8
Value
8.0
Installation
8.5
Warranty
8.0
3 Ton 17 SEER 96% AFUE 120,000 BTU Goodman Gas Furnace and Air Conditioner System - Downflow
Current Price
$3640
Check Price at HVACDirect → Shop Now at HVACDirect
Authorized dealer · Full manufacturer warranty
// Bottom Line
This Goodman system delivers strong efficiency numbers at a competitive price point, making it ideal for homeowners replacing aging equipment who want to maximize rebate eligibility. The 96% AFUE furnace paired with an 18 SEER1 air conditioner covers both heating and cooling needs without breaking the budget.

Review

The Goodman CAPF3743D6 represents a solid mid-market entry in the HVAC category, combining gas furnace and air conditioning in one downflow unit. At $3,640, it occupies the sweet spot where efficiency meets affordability, attracting homeowners replacing equipment from the 1990s and early 2000s. The system qualifies for Energy Star certification, which typically unlocks utility rebates that substantially reduce net cost. Goodman's market position relies on reliability without premium pricing, and this model follows that formula.

The furnace delivers 120,000 BTU heating output with 96% AFUE, meaning you're converting nearly all fuel to usable heat. The air conditioner provides 35,000 BTU cooling at 18 SEER1 efficiency, requiring a 3.5 ton capacity to cool 3 ton applications. Two-stage burners and a scroll compressor enable both units to modulate, reducing on-off cycling and improving comfort. The variable-speed ECM blower adjusts airflow from 0 to 2,000 CFM based on demand, avoiding the energy waste of fixed-speed motors.

Pros & Cons

Pros

  • 18 SEER1 cooling efficiency with two-stage scroll compressor for quiet, modulated operation
  • 96% AFUE heating with two-stage burner and ECM variable-speed blower for precise temperature control
  • Energy Star certified with rebate availability, potentially offsetting initial $3,640 cost
  • PVC exhaust compatible, simplifying installation in retrofit applications
  • 10-year warranty with online registration covers compressor and components

Cons

  • 71 dBA noise level runs louder than premium competitors, noticeable in quiet neighborhoods
  • 3.5 ton capacity slightly oversized for typical 3 ton applications, causing minor cycling inefficiency
  • Limited to R410A or R22 refrigerant, reducing flexibility as standards evolve

Who Should Buy

Best For

Homeowners in moderate climates looking to upgrade from older single-stage systems who prioritize upfront savings and rebate eligibility. Contractors installing in rental properties or value-focused residential projects will appreciate the balance of efficiency and affordability.

Consider Alternatives If

Buyers in ultra-quiet residential areas or those seeking premium brands should explore Carrier or Lennox alternatives, as the 71 dBA noise level may cause neighbor concerns.

3 Ton 17 SEER 96% AFUE 120,000 BTU Goodman Gas Fur
$3640
Buy at HVACDirect →

Installation

Installation complexity is straightforward due to PVC exhaust compatibility, eliminating costly masonry chimney retrofits. The downflow configuration suits basements and mechanical rooms with tight spaces, requiring only 30 inches of height clearance. Electrical demands are modest at 115V single-phase 60Hz with a 21.9 to 35 amp breaker range. A licensed HVAC technician should handle refrigerant lines, ductwork connections, and gas line pressure testing.

Warranty & Reliability

The 10-year warranty covers compressor, coil, and components when registered online within 30 days of installation. This duration is competitive for Goodman products but shorter than some premium brands offering 12 or 15 years. Registration is straightforward and essential to activate coverage. Parts labor is not covered, so service calls incur technician fees beyond parts replacement.

Specifications

SKUCAPF3743D6
Brand/ManufacturerGoodman
Cooling BTU35,000
Heating BTU120,000
RefrigerantR410A or R22
Electrical115 V. 1 Phase 60 Hz
Warranty10 Years with Online Registration
Decibel Level (dBA)71
Weight (in lbs)42.000000
FeatureSpec
Energy StarYes
SEER1 (Efficiency)18
Condenser StagesTwo Stage
Compressor TypeScroll
Liquid Valve Size3/8"
Suction Valve Size7/8"
Max Breaker Size35 amps
Min. Breaker Size21.9 amps
Tonnage3.5 Ton
Valve TypeSweat
Height30"
Width24.5"
Depth21"
ResourcesCAPF Installation Manual CAPF Specifications Sheet Goodman Evaporator Coil Warranty You will need Adobe® Acrobat® Reader to view PDF documents.
Safety InformationPROPOSITION 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 Number7368845
Airflow DirectionDownflow/Horizontal
Exhaust Flue RequirementPlastic / PVC
Product FeaturesRebate Available
Furnace Efficiency / AFUE96%
Blower MotorVariable Speed - ECM
Maximum CFM2000
ConfigurationUpflow / Downflow
Burner StagesTwo
Fuel TypePropane, Natural Gas
Liquid Line3/8"
Suction Line7/8"
StyleA-Coil

Frequently Asked Questions

Is this unit oversized for a 3-ton home? +
Yes, the unit is rated 3.5 tons while most 3-ton homes need exactly 3 tons. The oversizing can cause shorter run cycles, reducing efficiency gains. If your load calculation confirms 3 tons, request a 3-ton downflow model instead to optimize performance and humidity control.
Can I use this system with my existing ductwork? +
Downflow configuration works best with basement or crawl space installation feeding horizontal ducts to first-floor registers. If your home has upflow ductwork, you'll need costly rework. Verify your installation location allows downflow airflow before purchasing.
How does 18 SEER1 compare to older systems? +
An older 10 SEER system from 2005 costs roughly 45% more to operate annually. At current rates, the 96% AFUE furnace saves $400 yearly versus an 80% unit. Combined savings typically pay back the system cost in 8 to 12 years through rebates and utility reductions.
Should I choose this over a Lennox or Carrier unit? +
Goodman prioritizes value, Lennox focuses on comfort features, and Carrier emphasizes long-term durability. This unit outperforms budget brands but includes fewer smart controls. If rebates cover 30% of cost, Goodman wins on ROI. Lennox appeals to smart-home users willing to pay more.
Do I need an online registration to activate the warranty? +
Yes. Registration within 30 days of installation is required for the 10-year coverage to apply. Without registration, warranty defaults to a shorter period. Keep your receipt and AHRI certificate 7368845 handy for the registration process.

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