{"product_id":"fortress-power-envy-duo-21-whole-home-hybrid-solar-inverter","title":"Fortress Power Envy Duo 21 Whole-Home Hybrid Solar Inverter","description":"\u003ch6\u003e\u003cstrong\u003eDescription\u003c\/strong\u003e\u003c\/h6\u003e\n\u003ch1\u003e\u003cstrong\u003eFortress Power Envy Duo 21 Whole-Home Hybrid Solar Inverter\u003c\/strong\u003e\u003c\/h1\u003e\n\u003ch2\u003eProduct Description\u003c\/h2\u003e\n\u003cp\u003eThe Fortress Power Envy Duo 21 is a 48V hybrid solar inverter designed for demanding residential and light-commercial energy systems. It supports 240V split-phase and 208V three-phase configurations while delivering 12kW of continuous backup output across both configurations.\u003c\/p\u003e\n\u003cp\u003eThe inverter accommodates photovoltaic arrays up to 25kW, with a maximum usable PV power of 21kW. Integrated AC and DC breakers, a built-in rapid-shutdown transmitter and remote monitoring help simplify installation and ongoing system management.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e12kW continuous backup output at 240V or 208V\u003c\/li\u003e\n\u003cli\u003eMaximum grid output of 16kW at 240V\u003c\/li\u003e\n\u003cli\u003eMaximum grid output of 13.8kW at 208V\u003c\/li\u003e\n\u003cli\u003eSupports photovoltaic arrays up to 25kW\u003c\/li\u003e\n\u003cli\u003e21kW maximum usable photovoltaic power\u003c\/li\u003e\n\u003cli\u003eThree MPPTs with a 2:2:1 input configuration\u003c\/li\u003e\n\u003cli\u003eSupports 240V split-phase systems\u003c\/li\u003e\n\u003cli\u003eSupports 208V three-phase systems\u003c\/li\u003e\n\u003cli\u003eCompatible with Fortress Power 48V batteries\u003c\/li\u003e\n\u003cli\u003eSupports operation without a battery\u003c\/li\u003e\n\u003cli\u003eIntegrated AC and DC breakers\u003c\/li\u003e\n\u003cli\u003eBuilt-in rapid-shutdown transmitter\u003c\/li\u003e\n\u003cli\u003eSupports up to 10 inverters in parallel\u003c\/li\u003e\n\u003cli\u003eMaximum combined output of 120kW\u003c\/li\u003e\n\u003cli\u003eRemote system monitoring through the Fortress Power mobile app\u003c\/li\u003e\n\u003cli\u003eRemote firmware updates\u003c\/li\u003e\n\u003cli\u003eNEMA 4X and IP66 protection\u003c\/li\u003e\n\u003cli\u003eTouch color screen\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003cth\u003eDetails\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eManufacturer\u003c\/td\u003e\n\u003ctd\u003eFortress Power\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eModel\u003c\/td\u003e\n\u003ctd\u003eEnvy Duo 21\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGTIN\u003c\/td\u003e\n\u003ctd\u003e00850079800021\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum PV Array Power\u003c\/td\u003e\n\u003ctd\u003e25,000W\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Usable PV Power\u003c\/td\u003e\n\u003ctd\u003e21,000W\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNumber of MPPTs\u003c\/td\u003e\n\u003ctd\u003eThree\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInputs per MPPT\u003c\/td\u003e\n\u003ctd\u003e2:2:1\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Usable Input Current\u003c\/td\u003e\n\u003ctd\u003e26A \/ 26A \/ 15A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Short-Circuit Input Current\u003c\/td\u003e\n\u003ctd\u003e31A \/ 31A \/ 19A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePV Startup Voltage\u003c\/td\u003e\n\u003ctd\u003e100V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNominal MPPT DC Voltage\u003c\/td\u003e\n\u003ctd\u003e360V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDC Voltage Range\u003c\/td\u003e\n\u003ctd\u003e100–550V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMPPT Operating Voltage Range\u003c\/td\u003e\n\u003ctd\u003e120–440V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackup Output Current\u003c\/td\u003e\n\u003ctd\u003e50A at 240V \/ 57.7A at 208V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackup Output Voltage\u003c\/td\u003e\n\u003ctd\u003e120\/240V and 120\/208V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eContinuous Backup Output\u003c\/td\u003e\n\u003ctd\u003e12,000VA at 240V \/ 12,000VA at 208V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackup Operating Frequency\u003c\/td\u003e\n\u003ctd\u003e60Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePeak Backup Power\u003c\/td\u003e\n\u003ctd\u003eTwice rated power for 0.5 seconds\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackup THDv\u003c\/td\u003e\n\u003ctd\u003eLess than 3%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSwitching Time\u003c\/td\u003e\n\u003ctd\u003eLess than 20 milliseconds\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Grid Output Current with PV\u003c\/td\u003e\n\u003ctd\u003e66.7A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Grid Output with PV\u003c\/td\u003e\n\u003ctd\u003e16,000W at 240V \/ 13,800W at 208V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eContinuous Battery-Only Output\u003c\/td\u003e\n\u003ctd\u003e12,000W at 240V \/ 12,000W at 208V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRated Grid Voltage\u003c\/td\u003e\n\u003ctd\u003e120\/240V and 120\/208V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGrid Operating Voltage Range\u003c\/td\u003e\n\u003ctd\u003e180–270V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGrid Operating Frequency\u003c\/td\u003e\n\u003ctd\u003e50\/60Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGrid Frequency Range\u003c\/td\u003e\n\u003ctd\u003e55–65Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Factor\u003c\/td\u003e\n\u003ctd\u003e0.99 at full load\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eReactive Power Adjustment Range\u003c\/td\u003e\n\u003ctd\u003e-0.8 to +0.8 leading, adjustable\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eGrid THDi\u003c\/td\u003e\n\u003ctd\u003eLess than 3%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSynchronous Inrush Current\u003c\/td\u003e\n\u003ctd\u003e35A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatible Battery Type\u003c\/td\u003e\n\u003ctd\u003eLithium battery or no battery\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNominal Battery Voltage\u003c\/td\u003e\n\u003ctd\u003e48V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBattery Voltage Range\u003c\/td\u003e\n\u003ctd\u003e40–60V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Battery Charge Current\u003c\/td\u003e\n\u003ctd\u003e250A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Battery Discharge Current\u003c\/td\u003e\n\u003ctd\u003e250A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum PV-to-Grid Efficiency\u003c\/td\u003e\n\u003ctd\u003e97.50%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Battery-to-Grid Efficiency\u003c\/td\u003e\n\u003ctd\u003e94%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCEC Efficiency\u003c\/td\u003e\n\u003ctd\u003e96.90%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Parallel Units\u003c\/td\u003e\n\u003ctd\u003e10\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Combined Output\u003c\/td\u003e\n\u003ctd\u003e120kW\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003e22.3 × 35.2 × 11.2 inches\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMetric Dimensions\u003c\/td\u003e\n\u003ctd\u003e566 × 893 × 285 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e125.71 lbs \/ 57 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eProtection Rating\u003c\/td\u003e\n\u003ctd\u003eNEMA 4X \/ IP66\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCooling\u003c\/td\u003e\n\u003ctd\u003eSmart cooling fans\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTopology\u003c\/td\u003e\n\u003ctd\u003eHigh-frequency transformerless\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRelative Humidity\u003c\/td\u003e\n\u003ctd\u003e0–100%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Operating Altitude\u003c\/td\u003e\n\u003ctd\u003eLess than 6,561 feet \/ 2,000 meters\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temperature\u003c\/td\u003e\n\u003ctd\u003e-13°F to 140°F \/ -25°C to 60°C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTemperature Derating\u003c\/td\u003e\n\u003ctd\u003eAbove 104°F \/ 40°C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNoise Level\u003c\/td\u003e\n\u003ctd\u003eLess than 67dB\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAverage Idle Consumption\u003c\/td\u003e\n\u003ctd\u003e60W\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDisplay\u003c\/td\u003e\n\u003ctd\u003eTouch color screen\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCommunication\u003c\/td\u003e\n\u003ctd\u003eRS485, Wi-Fi and CAN\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEstimated Delivery\u003c\/td\u003e\n\u003ctd\u003eOne to two weeks\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch2\u003eFAQs\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eQ: How much continuous backup power does the Envy Duo 21 provide?\u003c\/strong\u003e\u003cbr\u003eA: It provides 12,000W of continuous backup output at either 240V or 208V.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What is the maximum supported solar-array size?\u003c\/strong\u003e\u003cbr\u003eA: It supports a photovoltaic array up to 25,000W, with maximum usable PV power of 21,000W.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Does the Envy Duo 21 support three-phase power?\u003c\/strong\u003e\u003cbr\u003eA: Yes. It supports 120\/208V three-phase applications as well as 120\/240V split-phase systems.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Can multiple Envy Duo 21 inverters operate together?\u003c\/strong\u003e\u003cbr\u003eA: Yes. Up to 10 units can operate in parallel for a combined output of 120kW.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Is a battery required?\u003c\/strong\u003e\u003cbr\u003eA: No. The listed battery configurations are lithium battery or no battery.\u003c\/p\u003e\n\u003cp\u003eWhole Home Solar hybrid inverter; Max 16KW ongrid and 12KW off-grid continous output;Max 25KW PV array; 200A transfer switch: IP 65 outdoor rated; pre-built AC \u0026amp;DC breakers; Built-in Apsmart RSD transmitter; 120\/240V Single and split phase, 120\/208V three phase, 127\/220V single \u0026amp; split phase; 50\/60HZ; breakers included\u003c\/p\u003e","brand":"Fortress Power","offers":[{"title":"Default Title","offer_id":48514613313754,"sku":"FP-850079800021","price":4898.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0704\/5283\/8618\/files\/Prodpage-2026-08-28T185741.042.png?v=1787958025","url":"https:\/\/powergenstore.com\/products\/fortress-power-envy-duo-21-whole-home-hybrid-solar-inverter","provider":"PowerGen Store","version":"1.0","type":"link"}