Renovating an old building without stripping it of its soul is a real challenge. But we took on that challenge with passion at the building on Rue du Vuache in Geneva. Designed in the 1930s by architect Julien Flegenheimer, this uniquely charming building needed a serious update to meet current energy standards—without compromising its heritage character. Between administrative constraints, heritage requirements, and tenants' expectations, every step was carefully planned to modernize without distorting.
Our objective is clear: to obtain the High Energy Performance (HPE) label. To achieve this, we launched a complete renovation, structured in phases starting in 2024.
We began with the thermal insulation of the façade. On the street side, we applied a 3.5 cm aerogel render to improve insulation while preserving the original look. On the courtyard side, we opted for 14 cm of wood wool insulation—a choice that is both high-performing and eco-friendly. We also took this opportunity to replace the windows to reduce heat loss and improve sound insulation—especially valuable given the building's proximity to railway lines.
Other major works were also required to meet our energy targets: we completely redid the roof, replaced the central glass canopy in the entrance hall, and insulated the basement ceiling to further boost the building’s energy efficiency.
We are currently transforming the heating system by installing four air-to-water heat pumps, which will permanently replace the old gas heating system. This key stage of the project requires careful coordination, as the work involves ventilation shafts located directly in tenants’ apartments (see photos below). Since these interventions take place inside the apartments, we are fully committed to ensuring everything runs as efficiently and respectfully as possible.
Even before construction began, we organized information sessions to present the project, engage with tenants, and answer their questions. Throughout the works, we remain attentive and dedicated to maintaining the best possible living conditions.
Next step: by September 2025, we will install thermal and photovoltaic solar panels on the roof to maximize the building’s energy autonomy.
Ultimately, thanks to our efforts, the building’s heat consumption index will be cut in half—a performance officially recognized through the HPE label.
We’re proud to show that with expertise and commitment, tradition and modernity can go hand in hand. See you in September 2025 for the final result!
You can read the full article at the end of this post : link
