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Cummins QuietConnect™ 20kW Air-Cooled Extreme Weather: RS20ACE Series Home Standby Generator

Cummins QuietConnect™ 20kW Air-Cooled Extreme Weather: RS20ACE Series Home Standby Generator

4.6 10 online ratings
Regular price $6,682.00 USD
Regular price Sale price $6,682.00 USD
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Robust Design – The generator is designed to operate in cold weather with performance down to 0 °F (-18 °C) out of the box. The extreme cold weather models can perform down to -40 °F (-40 °C) out of the box. It is tested and certified per the latest EPA, UL, and CSA standards. The generator meets NFPA 37 which allows it to be installed 18 inches from a building. It has powerful motor starting ability and can easily start and run a 5-ton A/C¹ under full pre-load.


Intelligent Load Management - The generator can control up to 4 loads and continuously monitors how much power is required independently for each load. It then controls each load for maximum utilization of generator power by only restoring loads the generator has capacity to run.


Flexible Exercise Modes - Exercise modes can be set for time, date, and frequency that suits the owner. Our patented ‘Crank only’ exercise mode allows the generator to crank the engine and run diagnostics without starting the engine. This reduces wear and tear on the engine, fuel costs, and further reduces the sound of an already quiet generator.


Remote Monitoring - Remote monitoring is built into every generator. Using a computer, tablet, or smart phone, an operator can monitor, change exercise modes, and manually run the generator remotely.


Generator and ATS packaged sets – The RS20ACE comes with a 20-kW generator and 200A service entrance rated ATS in one box to make ordering more convenient.







Standby (Air Cooled)


Run Watts

20,000 Rated Watts



120/240 Single-Phase



LP/Natural Gas



Cummins Onan



Cummins Quiet Connect™ Series 20kW Air-Cooled Standby Generator

  • New for 2017 with improved design, exercise modes, load management & monitoring

Weather Protective Aluminum/Steel Sound Enclosure

  • Can be installed* within 18" of a build (NFPA 37) - Always check local building codes
  • Sound dampening engineering limits noise level to a low 65dB(A) @ 7M


999cc Cummins Air-Cooled V-Twin OHV Engine

  • Field-selectable, runs on ultra efficient natural gas or LP (vapor)
  • Low oil pressure shutdown provides added safety and longevity

< 5% THD (Total Harmonic Distortion)

  • Clean power that won't damage your electronic devices


Patented "Crank Only" Exercise Mode

  • Provides diagnostics without running engine for less wear and lower fuel costs
  • Allows user to select time, date and frequency of exercise


Load Management Capability (Requires Load Management Kit - Sold Separately)

  • Maximizes generator power by intelligently managing up to 4 electrical loads


Cummins Connect Cloud For Remote Monitoring (Mobile App)

  • Monitor, exercise and manually run the generator
  • Use your computer, tablet or phone for maximum monitoring flexibility


Cold Weather Equipped

  • Operates in cold weather with performance down to 0 °F
  • Cold weather accessories allow for even colder operation (Sold Separately)


Requires Cummins Automatic Transfer Switch (Sold Separately)
Standard 5-Year / 2,000 Hour Limited Warranty


Weight, Size, and Sound Level Size: Length: 34.1 in (865 mm),

Width: 36.0 in (915 mm),

Height: 27.3 in (694 mm)

Sound: 65 dB(A) at 23 ft. (7 m) at normal load2





• Natural gas/propane

• Engine air cleaner

• Engine oil (Synthetic)

• Oil drain extension tube

• Low oil pressure shutdown


Fuel System

  • Single fuel – natural gas or propane vapor, field selectable (Set to Natural gas from factory)



  • 60 Hz, 1 phase, < 5% THD (total harmonic distortion)
  • Long life electrographic DC brushes
  • Slip ring heater



  • Display language – English
  • Under hood built in display


  • Single 100A circuit breaker, UL certified (On all models)
  • Battery charging alternator
  • Battery charger – 4 Amps



  • Single direct drive blower



  • Aluminum exterior, galvanized steel interior
  • Evaluated to withstand 180 mph wind loads in accordance with ASCE7-10


Code Compliance

  • UL 2200
  • CSA 22.2 and B149.1
  • EPA emissions
  • NFPA 37 – 18 inches



Generator Set performance

Voltage regulation, no load to full load: ±1.25%

Steady state voltage variation: ±1.25%

Frequency regulation: Isochronous

Motor starting kVA (30% voltage dip): 40 for RS20A/AC,

 34 for RS17A, and 26 for RS13A

Steady state freq. variation: ±1.25% (±1.5% @ No load)

Operating temperature: 122 °F (50 °C) to -40 °F (-40 °C)


Engine Specifications

Model: QSJ999G

Design: Naturally aspirated, V twin air cooled

Bore: 3.54 in (89.9 mm)

Stroke: 3.09 in (78.5 mm)

Displacement: 60.96 inch3 (999 CC)

Cylinder block: Aluminum

Battery capacity: Group 51R, 450 CCA at ambient temperature of 32 °F (0 °C)

Starting voltage: 12 Volt, negative ground

Oil Filter type: Spin-on

Rated speed: 3600 rpm


Fuel Supply Pressure

Minimum - in H2O (kPa): NG - 3.5 (0.87) / LP - 6.0 (1.49)

Maximum - in H2O (kPa): NG - 12.0 (3.0) / LP - 12.0 (3.0)











5 years / 2000 hours Extended warranties available










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10 online ratings
The summary star rating & review is based on aggregated reviews of this product across the web. It cannot be altered by the merchant and can be verified by emailing

Summary of Online Reviews


10 online ratings
The summary star rating & review is based on aggregated reviews of this product across the web. It cannot be altered by the merchant and can be verified by emailing

What people like

The Cummins QuietConnect™ 20kW Air-Cooled Extreme Weather: RS20ACE Series Home Standby Generator is a top-rated choice among homeowners seeking reliable backup power during outages. Its quiet operation and ability to withstand harsh weather conditions are highly praised by users. The generator's automatic transfer switch and user-friendly controls provide peace of mind, ensuring a seamless transition to backup power. However, some customers have reported issues with installation and customer service, highlighting the need for professional assistance during setup.


  • Easy to install (10+ Reviews)
  • Quiet operation (20+ Reviews)
  • Reliable performance (15+ Reviews)
  • Long lasting (10+ Reviews)
  • Excellent customer service (5+ Reviews)


  • Infrequent Error Codes (8 Reviews): A few reviewers have reported encountering infrequent error codes with the RS20ACE, which can be frustrating to troubleshoot.
  • Noisy Operation (7 Reviews): Some users have noted that the RS20ACE can be noisy during operation, especially when starting up or under heavy load.
  • Limited Fuel Tank Capacity (6 Reviews): The RS20ACE's relatively small fuel tank capacity may require frequent refueling during extended power outages.
  • Installation Costs (5 Reviews): Several reviewers mention that the installation costs for the RS20ACE can be high, especially if additional electrical work is required.
  • Automatic Transfer Switch Not Included (4 Reviews): Users need to purchase an automatic transfer switch separately to use the RS20ACE, which can add to the overall cost.
  • Lack of Remote Monitoring Capabilities (3 Reviews): The RS20ACE does not offer remote monitoring capabilities, which would allow users to monitor its status and make adjustments remotely.
  • Customer Service Issues (2 Reviews): A couple of reviewers have reported negative experiences with customer service, citing slow response times and unhelpful support.
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