High-Efficiency Power Management

Rheem is proud to offer the SEREGEN® 300 Series 20kW Home Generator System. Boasting a 993cc commercial Vanguard™ engine and 28,000 watts of starting power, the system offers whole house comfort & control in an extremely compact & affordable package. The standard 20kW package will supply enough automatic backup power to manage two 5-ton AC units. The optional Power Management System upgrade optimizes the SEREGEN 300 Series with advanced computer-controlled power for maximum efficiency.

Fully Automatic – Advanced electronics will detect a utility power outage and automatically start the generator whether you are home or away.

Whole House Comfort – The SEREGEN 300 Series will supply enough power to manage up to two 5-ton air conditioners in addition to essential household power requirements.

Vanguard™ 993cc Engine – An industry leading commercial grade Big Block™ air-cooled engine provides powerful, quiet, durable performance for large, power hungry homes – perfect for years of heavy-duty standby power.

Continuous Fuel Supply – A permanent connection to natural gas or propane delivers uninterrupted performance with no messy gasoline storage and refueling.

Sound Shield™ Technology – engineered air passages, an automotive-style exhaust system and acoustic foam dampeners ensure quiet operation. (68dB under normal operation)

Turn Key Extras – each system includes a battery charger, hour meter, and installation pad. The engine also comes pre-filled with synthetic oil and is broken in at the factory, saving you time and money.

Premium Warranty – 4 year limited – your guarantee of quality and performance.

Legendary Service & Support – From professional sizing and delivery to installation and service, trust the proven experts at Rheem for complete peace of mind.


  • Lights
  • Furnace Fan
  • Refrigerator/Freezer
  • Garage door opener
  • Security System
  • Humidifier/dehumidifier
  • Entertainment System
  • Sump Pump
  • Outside Lighting
  • Microwave
  • Central Air Conditioner 1
  • Central Air Conditioner 2
  • Range/Stove
  • Dryer
  • Water Well pump
  • Hot Tub
  • Pool Heater
  • Water Heater



Model GEN20AD

  • Fully Automatic Start
  • Provides Whole House Comfort
  • Industrial Strength Engines
  • Continuous Fuel Supply from Natural Gas/Propane
  • Sound Shield™ Technology
  • Contemporary Space Saving Design
  • Durable Outdoor Enclosure


Product Sheet
Stat Station Instruction Manual
Indoor Load Monitor Manual
Generator Batteries
Installation Manual
GEN30LP, GEN30NG Installation and Startup Manual