Built around 1900 and accompanied by an 18th-century barn, this historic property in Königstein presented a rare opportunity: to preserve the architectural character of two very different buildings while transforming them fundamentally for contemporary life.

From the outset, the project required patience, persistence and an unusual degree of coordination beyond the conventional planning process. The proposed transformation encountered considerable regulatory challenges, and the initial building application was not approved. In close collaboration with legal and specialist advisers, the planning had to be substantiated and pursued through an extensive approval process before the architectural vision could be realised.

One of the key interventions was the removal of an unsympathetic later addition between the Wilhelminian house and the historic barn. Although architecturally desirable, the intervention required detailed environmental and species-protection assessments before approval could be obtained.

The challenges continued during construction. Further administrative and regulatory issues repeatedly required clarification and, in some cases, legal support. Managing these parallel processes while maintaining progress on site became an important part of the overall project coordination.

The architectural transformation itself was guided by a simple principle: to preserve what gives the buildings their identity while allowing them to perform as contemporary homes. Original proportions and architectural qualities were carefully recovered, while façade, windows, roof, building technology and interior architecture were considered as interconnected parts of the same transformation.

This approach extended to the energy concept. Integrating photovoltaic technology into the historic roofscape was initially not approved and had to be carefully substantiated and pursued through a separate approval process.

Four years of operation now demonstrate the result: the two historic buildings are entirely free from fossil-fuel-based heating and, over the course of a year, produce more energy than they consume.

The balance is seasonal. During the summer months, the photovoltaic system generates substantial surpluses, while electricity still has to be drawn from the grid during winter. Across the year, however, the property currently produces an overall surplus of approximately 4,000 kWh.

The next step is already underway: expanding battery storage to retain more of the energy generated on site and further reduce the amount of electricity that needs to be purchased from the grid.

The result is an ensemble that neither freezes its history nor erases it. Its original character remains tangible, while architecture, technology and energy performance have been carefully brought into the present.

For a Wilhelminian house and an 18th-century barn, this is perhaps the most meaningful expression of the project’s underlying idea: preserving architectural heritage does not mean preserving the way a building once performed. Historic architecture and a forward-looking energy concept can become part of the same transformation.