The Challenge:

The building had a solid structural foundation but no longer met current energy standards. High heat losses through the facade, roof, and basement ceiling resulted in excessive energy consumption and correspondingly high operating costs. The goal was to bring the building up to new-build performance, significantly reduce CO₂ emissions, and secure affordable housing for the long term.

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The Approach:

At the core of the retrofit was a complete renewal of the building envelope using prefabricated facade elements with integrated windows, insulation, and ventilation units — complemented by new roof insulation and basement ceiling insulation. In parallel, the building systems were fully upgraded: a new heating system supplies the building with heat and hot water, a controlled ventilation system ensures consistently good air quality, and a rooftop photovoltaic system generates renewable energy for building operations. The high degree of prefabrication enabled fast, precise on-site installation — with significantly less disruption for residents than a conventional retrofit.

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The Result:

The building now meets the EH 55 EE efficiency standard and energy efficiency class A+. Energy demand dropped by 80.7%, and CO₂ emissions fell from 88.5 to 10.1 tonnes per year — with a final energy demand of 31.5 kWh/m²a. For GWW, the project demonstrates that serial renovation works economically in occupied buildings and can be scaled across their wider portfolio.