The Lavater School complex in Zurich, an architectural gem dating back to 1896/97, has recently undergone a comprehensive refurbishment that marries heritage conservation with modern energy efficiency. Designed by city architect Gustav Gull in the style of the Swiss National Museum, the building is an outstanding example of late 19th-century school architecture. The renovation carefully balances the preservation of historic character with the demands of contemporary use and sustainability.
A central focus of the project was the restoration of the school’s original timber windows. Specialists from Holzmanufaktur Rottweil, experts in historic window restoration, meticulously renovated the windows to meet heritage preservation requirements, while upgrading them with modern insulating glazing. The project incorporated the Swisspacer Ultimate high-performance warm edge spacer, ensuring a thermally efficient glazing edge without compromising the building’s historic aesthetics.
The renovation also involved the sensitive restoration of the sandstone façade and the installation of automatically controlled fabric awnings to provide summer heat protection. Where possible, the historic interior glass was retained, while the exterior received Planiclear and ECLAZ ONE-coated insulating glazing, providing superior energy performance and durability. Installation required careful planning, including cranes and specially designed transport boxes for upper-floor windows, highlighting the complexity of modernizing heritage structures.
The upgraded glazing achieves a Ug value of 1.4 W/m²K, a technically balanced and economically feasible performance metric. The combination of this insulating glazing with Swisspacer Ultimate results in a highly energy-efficient construction that respects the school’s historical integrity. Dirk Obser, project manager at Holzmanufaktur Rottweil, emphasizes that the discreet design and excellent Psi-values of Swisspacer Ultimate were crucial in meeting both technological and aesthetic requirements. 
The Lavater School renovation exemplifies how historic buildings can embrace modern sustainability standards without losing their original character. By integrating cutting-edge glazing technologies with meticulous craftsmanship, the project demonstrates that energy-efficient solutions and heritage preservation can coexist, providing functional, sustainable, and visually authentic spaces for future generations.
Source: lifepr.de with additional information added by Glass Balkan
