Fortress Power Envy Duo 21 Inverter | 25kW PV Input | 12kW Continuous Output | Dual-Phase Compatible

Fortress Power Envy Duo 21 Inverter | 25kW PV Input | 12kW Continuous Output | Dual-Phase Compatible

Maximum Power. Dual-Purpose Design. Built for What’s Next.

The Fortress Power Envy Duo 21 is a high-output, 48V hybrid inverter built to meet the needs of advanced residential and light commercial energy systems. With up to 25kW of solar PV input, dual-phase compatibility, and seamless integration with Fortress Power’s 48V battery line, the Envy Duo 21 is the ideal solution for whole-home backup, net metering, and smart energy management.

Supporting both 240V split-phase and 208V three-phase systems (with parallel installation), the Envy Duo 21 delivers 12kW of continuous output and up to 16kW peak export—making it a powerhouse for demanding energy applications.

Key Features:

• Massive PV Input Capacity: Bring in more solar with up to 25kW of PV input, allowing larger arrays to operate at full potential. Ideal for properties with high energy loads or oversized solar arrays.
• Dual Voltage, Dual Purpose: Supports both 240V split-phase (residential) and 208V three-phase (light commercial) systems. Whether you're powering a home or a small business, the Envy Duo 21 adapts to your needs.
• Note: Three-phase requires two or more inverters in parallel.
• Whole-Home Backup with Fortress Battery Integration: Pairs perfectly with Fortress Power 48V batteries (e.g., eVault MAX, eFlex MAX, eForce), providing:
  • 12kW of continuous output
    
  • Up to 16kW of export power
    
  • Reliable power for essential loads, appliances, HVAC systems, and more.
    
• Scalable to 120kW Output: Parallel up to 10 Envy Duo 21 units for a total of 120kW of AC output, making it ideal for growing systems, small commercial sites, and microgrids.
• Installer-Friendly with Built-In Hardware:
  • Integrated AC/DC breakers
    
  • Built-in rapid shutdown transmitter
    
  • Simplifies installation and ensures NEC 2017/2020 compliance
    
  • Reduces time, labor, and external hardware requirements
    
• Smart Monitoring + Remote Updates: Control and monitor your system via the Fortress Power mobile app, featuring:
  • Real-time solar, battery, and grid stats
    
  • Historical performance analytics
    
  • Remote firmware updates—no site visit needed
    

Applications:

• Large residential solar + storage systems
  
• Light commercial buildings
  
• Off-grid & grid-tied backup systems
  
• Net metering and load shifting
  
• Time-of-use optimization and zero-export
  
• Virtual Power Plant (VPP) participation
  

What’s Included:

• 1 × Fortress Power Envy Duo 21 Hybrid Inverter
  
• Integrated AC & DC Breakers
  
• Built-in Rapid Shutdown Transmitter
  
• Mounting Hardware
  
• Fortress Power Mobile App Access
  
• User Manual & Warranty Card
  

Requires minimum of two inverters for 208V three-phase applications.

Specifications

Shopping Guide

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