The recently renovated Palác Dunaj office building, located at the intersection of Národní and Voršilská streets in central Prague, has been awarded the LEED Gold certificate for sustainability. The certification, issued by the U.S. Green Building Council, is notable due to the building’s historical status and the challenges involved in upgrading older properties to modern environmental standards. The 1920s-era building underwent a renovation managed by Zeitgeist Asset Management, in collaboration with heritage conservation authorities and sustainability consultant Grinity. The project involved adapting the original constructivist structure to meet current environmental criteria without altering its architectural character. The LEED Gold certification required meeting multiple criteria across environmental performance, material use, and energy efficiency. Due to the building’s location in Prague’s historic core, space constraints limited the ability to stage traditional construction logistics. Materials were lifted onto the roof by crane, and waste segregation had to be managed using a single container at a time. Despite these limitations, the project achieved a 90% recycling rate of construction and demolition waste. Material selection played a key role in meeting LEED standards. The project used 26 materials with verified environmental product declarations (EPDs), over 15% of which included recycled content. The team also adhered to stricter-than-usual requirements on chemical content disclosure, meeting REACH standards at a 100 ppm accuracy level—well beyond the typical 1,000 ppm used in most European regulations. A green roof was also introduced, covering 31.5% of the roof area. It includes locally appropriate plantings and a drip irrigation system, eliminating the need for potable water for irrigation. This element contributed points in several LEED categories, including site sustainability and water efficiency. The building received high marks for energy performance, achieving a 22.6% energy saving compared to the LEED baseline. Technical equipment had to be installed within the constraints of the existing structure, particularly in the lower basement levels, adding to the complexity of achieving these results. In total, the renovation earned 64 points under the LEED system, securing the Gold level. A separate WELL certification process is ongoing, with the goal of also reaching the Gold level for interior environmental quality. Palác Dunaj now offers 6,700 square metres of office space and 2,000 square metres of retail space. Tenants include several EU institutions, the Czech Bar Association, law firm CMS, and Taro restaurant. Architectural firm Chapman Taylor led the design work, which preserved original features such as travertine walls, a central atrium with a paternoster lift, and terrazzo floors. Some commercial and office units in the building remain available for lease.