BERLIN, March 7, 2026 /PRNewswire/ — Fox ESS, a leading provider of renewable energy solutions, has announced a significant milestone in energy storage efficiency. The company has achieved a record System Performance Index (SPI) of 97%, securing the top position and earning an Efficiency Class A ranking in the storage category by HTW Berlin and AQUU Research.
HTW Berlin, a leading German university of applied sciences, is internationally recognized for its rigorous research in energy storage technologies. Its annual ‘Energy Storage Inspection’ reports are regarded as some of Europe’s most credible evaluations, thoroughly assessing energy storage systems under practical conditions.
“This SPI of 97% is more than just a number; it embodies our steadfast commitment to innovation and excellence in energy storage solutions. We are dedicated to advancing the Energiewende initiative, ensuring that everyone can benefit from reliable and sustainable solar energy.” said Christoph Schön, the General Manager of DACH region at Fox ESS.
Record Performance
The latest report reviewed 12 systems, of which 8 were evaluated using the SPI (10 kW) metric. Fox ESS’s system, featuring the PQ-H3-Ultra-10.0 inverter and the EQ3300-5 battery, achieved a groundbreaking SPI of 97%. This high efficiency reflects Fox ESS’s optimized design, which minimizes energy conversion losses and enhances overall system reliability for residential users.
Ongoing Success
Last year, Fox ESS’s H3 Hybrid Inverter and ECS system achieved an A-Class rating with a performance index of 94.8% in the 10 kW residential storage system test. Additionally, earlier this year, the S&P Global Energy Residential Storage Index ranked Fox ESS as the No. 1 market share leader in Europe. In 2023, the company was also listed on Forbes’s Unicorn List, further solidifying its prominent position in the industry.
In the past three years, Fox ESS has installed over 890,000 PV inverters and more than 1 million batteries across over 70 countries. Looking ahead, the company remains committed to technological innovation, striving to deliver high-performance products tailored to customer needs.
About Fox ESS
Founded in 2019 and headquartered in Wenzhou, China, Fox ESS is a national high-tech enterprise specializing in the R&D, production, sales, and service of renewable energy power equipment, with a strong focus on advanced power electronics. Committed to global growth, Fox ESS has established a presence in over 70 countries and regions, forging more than 200 partnerships that drive innovation across Asia, Europe, the Americas, Africa, and Oceania. Guided by a customer-first philosophy, we deliver high-efficiency renewable energy solutions worldwide through innovation and exceptional value.