BERLIN, March 7, 2026 — Fox ESS, a top renewable energy solutions provider, has reached a major efficiency milestone for its energy storage systems. The company attained a record System Performance Index (SPI) of 97%, clinching first place and receiving an Efficiency Class A designation in the storage category from HTW Berlin and AQUU Research.

HTW Berlin, a premier German university of applied sciences, is globally acknowledged for its stringent research into energy storage technology. Its yearly ‘Energy Storage Inspection’ reports are considered among Europe’s most authoritative assessments, comprehensively testing energy storage systems in real-world scenarios.

“Achieving an SPI of 97% represents more than a figure; it signifies our unwavering dedication to innovation and quality in energy storage. We are focused on supporting the Energiewende, guaranteeing that all can access dependable and sustainable solar power,” stated Christoph Schön, General Manager for the DACH region at Fox ESS.

Record Performance

The recent report examined 12 systems, with 8 of them assessed using the SPI (10 kW) measure. The Fox ESS system, which utilizes the PQ-H3-Ultra-10.0 inverter and EQ3300-5 battery, reached a pioneering SPI of 97%. This exceptional efficiency demonstrates the company’s refined design, which reduces energy conversion waste and boosts total system dependability for homeowners.

Ongoing Success

In the previous year, the Fox ESS H3 Hybrid Inverter and ECS system secured an A-Class rating with a 94.8% performance index in the 10 kW residential storage test. Furthermore, at the start of this year, the S&P Global Energy Residential Storage Index identified Fox ESS as the European market share leader. The firm was also named to the Forbes Unicorn List in 2023, reinforcing its standing as an industry leader.

Over the last three years, Fox ESS has deployed more than 890,000 PV inverters and over 1 million batteries in more than 70 nations. Moving forward, the company continues to prioritize technological advancement, aiming to provide high-performance products designed for client requirements.

About Fox ESS

Established in 2019 with its headquarters in Wenzhou, China, Fox ESS is a national high-tech company focused on the research, development, manufacturing, sales, and support of renewable energy power equipment, emphasizing advanced power electronics. Dedicated to international expansion, Fox ESS operates in over 70 countries and regions, forming more than 200 collaborative partnerships that foster innovation throughout Asia, Europe, the Americas, Africa, and Oceania. Driven by a customer-centric approach, we provide efficient renewable energy solutions globally via innovation and superior value.

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