Farmhouse in Lower Saxony heats hot water with photovoltaic electricity

The century-old farmhouse in the district of Nienburg/Weser faced a challenge: the wood chip heating system (Fröling T4 with 30 kW) installed in 2017 was ideal for heating the spacious rooms of the farmhouse, which spans approximately 340 m², during the winter. However, in summer, the heating system was oversized for hot water production. To address this issue, a photovoltaic system was installed in 2021 with a capacity of 9.7 kWp. In 2022, it was expanded to a total of 14.2 kWp, laying the foundation for a sustainable energy future.

Efficient utilization of photovoltaic surplus

The surplus energy generated by the photovoltaic system is efficiently utilized through the AC ELWA-E (the predecessor to the AC ELWA 2) from my-PV. This innovative technology converts surplus electricity directly into heat, supporting hot water preparation, especially in summer when heating needs are low. Now, the farmhouse can rely almost entirely on solar energy for hot water production in the summer, while in winter, the surplus electricity serves as heating support. Of the 60 m³ of hot water consumed annually, over 65% is generated with the AC ELWA-E using surplus photovoltaic electricity!

Why not solar thermal?

The farmhouse owner, Mr. Hormann, consciously chose not to install solar thermal collectors and instead opted for the use of photovoltaic surplus. The reasons for this decision include lower complexity, an increased self-consumption rate, and a flexible, linearly controllable regulation provided by the AC ELWA-E. This approach maximizes the use of surplus electricity on-site rather than selling it back to the grid at low feed-in tariffs.

Experiences from practice: A satisfied customer

“The AC ELWA-E operates flawlessly. In summer, we can completely turn off the wood chip heating system and cover our hot water needs with solar energy. This has significantly improved the self-consumption of my photovoltaic system,” reports Mr. Hormann with satisfaction.

By combining photovoltaic technology with my-PV's solutions, Mr. Hormann has made his farmhouse more efficient and environmentally friendly—a step that pays off both economically and ecologically.

Curious about the consumption data?

You can view the data on solar coverage and hot water production directly through the my-PV Cloud demo view—just one click, and you’ll see the real-time usage!