Climate protection award for a heritage multi-family house: Photovoltaic heat in a historic building

How can a photovoltaic system be integrated into a heritage-protected building without violating strict preservation regulations? Builder Patrick Reißner from Konstanz found an innovative solution: instead of mounting the 9.8 kWp PV system on the main building, it was installed on an existing prefab garage, making use of already sealed space in a creative and sustainable way.

Maximizing self-consumption with photovoltaic heating

The PV system supplies electricity to the common areas of the multi-family house, rather than directly to individual apartments. Initially, this resulted in a high amount of surplus energy being fed into the grid. However, since 2023, the system includes two AC ELWA 2 photovoltaic heating elements from my-PV. They enable seamless regulation of surplus solar energy for heating water with photovoltaics. Otherwise, this energy would be fed into the grid unused. The energy is efficiently stored in two 850-liter stratified buffer tanks, providing hot water and additional heating support.

"Since a heat pump was not an economical option for this building, we chose the PV heating rods from my-PV. The ability to flexibly use surplus energy for heating was a decisive advantage for us," explains Patrick Reißner.

With the addition of a 12 kWh BYD battery storage system in summer 2024, self-consumption of solar power has been further optimized. The intelligent energy management provided by a SolarEdge Home Energy Meter ensures that battery storage is prioritized before surplus energy is used for heating and hot water.

Open-system architecture and heritage-friendly implementation

This renovation project demonstrates that even heritage buildings can benefit from modern energy solutions with careful planning. A key requirement was avoiding any structural modifications to the historic building. Therefore, the PV system was placed on an existing structure and equipped with SolarEdge power optimizers to ensure maximum energy yield despite occasional shading.

Also, for heating, a sustainable hybrid system was implemented: during the winter months, when solar energy is insufficient, a pellet and firewood heating system provides additional support.

Patrick Reißner reflects positively on the project: “The AC ELWA 2 from my-PV was the ideal solution for us, enabling an economical and sustainable heating supply. Not only do we save on energy costs, but we also contribute significantly to climate protection.”