The Frank family embraced solar power back in 2004, long before it became popular. Their system at the time was designed for full feed-in to the public grid and, for years, ensured a stable feed-in tariff. However, after almost two decades, it was clear that the future of energy would look different. The family decided to take the next step towards achieving full independence in terms of their electricity, heating and mobility. Together with HKM and EcoFlow, the outdated system was transformed into a future-ready all-in-one energy solution.

The motivation for the change came from a common situation: the 20-year-old gas heating system needed replacing and an alternative was required. Thanks to government subsidies and technical feasibility, the choice fell on a heat pump. This also led to a rethink of the entire electricity supply. “We wanted to have power available for the heat pump as early in the day as possible,” explains Alfons Frank. “So we added to the existing south-facing system and installed new PV modules on the east side.” This marked the beginning of the journey towards self-sufficiency, with a new energy setup on the roof and intelligent controls in the basement.

As part of the project, the original feed-in system from 2004 was completely replaced. The goal was to build a hybrid solution that combines old and new intelligently: · New PV system with 9.89 kWp · Additional 6 kWp to replace the old array · Two EcoFlow inverters: One still used for feed-in with compensation One for self-consumption and energy storage “The good old Sunny Boy has done its duty,” says solar technician Boris Christof with a wink. “Now two EcoFlow systems work hand in hand, one still feeding in, the other already operating in self-consumption mode.”

· PowerOcean Plus with 15 kWh storage capacity · Hybrid inverter for flexible energy distribution · Heat pump & heating rod for year-round heating · EcoFlow Power Insight app for transparency & control · EV charging solution already prepared As part of the conversion, the entire house installation, including intelligent meter technology, smart metering and modern switchgear, was also renewed. At the end of 2025, after the feed-in tariff expires, the second inverter will also be integrated into the self-supply system. Early Results: More Self-Sufficiency Month by Month In March 2025, the new system generated 1,058 kWh of solar power, despite cool temperatures and heating needs. The result: a self-sufficiency rate of over 57%, up 25% from the previous month. “I hope we’ll reach 80%,” says Johanna Frank. “But even now, it’s fascinating to see how much control we have—what’s running in the house, what could be optimized.” Over the course of the year, the battery already covers about 30% of their total electricity needs—and significantly more during the winter months.

Reliability & Build Quality: Aluminum housing instead of plastic Modularity: Batteries can be expanded and adapted at any time Intuitive Control & Strong Support Future-Proof Architecture: for electricity, heating, and e-mobility “I visited the EcoFlow production facility myself,” says Boris Christof. “The system impresses with its build quality, performance, and scalability.”

The Frank family has taken the logical next step with the EcoFlow system, transitioning from a classic feed-in system to achieving full self-sufficiency in terms of electricity, heating and, soon, mobility. Once the feed-in tariff expires at the end of the year, the system will be fully converted for self-consumption, boosting energy independence even further.