Fortress Power Envy Duo 21G Whole Home Solar Hybrid Inverter Envy Duo 21G

The Fortress Power Envy Duo 21G is a powerful 48V hybrid inverter engineered for large residential and light commercial solar-plus-storage systems. Designed to support up to 25kW of PV input, the Envy Duo 21G delivers 12kW of continuous backup power with battery operation and up to 16kW maximum grid export power. Supporting both 120/240V split-phase and 120/208V three-phase installations, it offers exceptional flexibility for a wide range of applications. 

The inverter features three independent MPPTs, integrated AC/DC breakers, a built-in rapid shutdown transmitter, and native compatibility with Fortress Power 48V battery systems. Parallel capability for up to ten inverters allows installers to build systems delivering up to 120kW of total output, making the Envy Duo 21G an ideal solution for scalable energy storage installations. 

Key Technology

• 25kW PV Input Capacity
  Supports large residential and light commercial solar arrays with exceptional solar harvesting capability.

• Three Independent MPPTs
  Three MPPT trackers maximize production across multiple roof orientations and varying shading conditions.

• Dual-Voltage Compatibility
  Supports both 120/240V split-phase and 120/208V three-phase electrical systems.

• 12kW Continuous Backup Output
  Provides dependable backup power for whole-home and light commercial applications.

• 16kW Maximum Grid Export
  High export capability maximizes solar production and grid interaction.

• Parallel Expansion
  Supports up to ten inverters operating together for systems up to 120kW.

• Integrated Protection
  Includes built-in AC/DC breakers, AFCI, surge protection, rapid shutdown transmitter, and comprehensive grid protection.

• Smart Monitoring
  Integrated RS485, CAN, and Wi-Fi communications with a full-color touchscreen display simplify commissioning and monitoring.

Best Uses

• Whole-Home Backup Systems
  Provides dependable backup power during utility outages.
• Large Residential Solar + Storage
  Perfect for homes with high electrical demand and battery storage.
• Light Commercial Installations
  Ideal for offices, retail locations, and small commercial facilities.
• Microgrid Applications
  Supports off-grid, grid-interactive, and hybrid operating modes.
• Scalable Energy Storage Projects
  Parallel capability allows future system expansion without replacing existing equipment.

Warranty

• Standard Warranty: 10 Years
• Battery Platform: 48V Lithium
• Maximum PV Array: 25kW
• Maximum Parallel Systems: 10 Units (120kW)

Product Specifications

Scalable Hybrid Power for Large Solar and Energy Storage Systems

The Fortress Power Envy Duo 21G combines high PV input capacity, advanced hybrid inverter technology, integrated protection, and scalable parallel operation into a powerful energy management solution for today's demanding residential and light commercial solar installations. Whether operating in backup, self-consumption, off-grid, or grid-interactive applications, the Envy Duo 21G delivers exceptional performance and long-term reliability.

Why Buy From US Solar Supplier

US Solar Supplier is an American-founded company based in Kentucky dedicated to offering top-quality solar components from trusted manufacturers. We provide competitive pricing, dependable inventory, and products backed by warranties you can trust.

Our inventory is updated daily with the latest solar technologies, and our experienced team is ready to assist with product selection, system design, and installation guidance.

Need Assistance?

Have questions before you order? Call 1-800-230-7004 to speak with our knowledgeable support team. We're here to help with product compatibility, battery sizing, system design, or purchasing support.