Preserving Heritage, Enhancing Efficiency: Passive Technologies for Achieving Zero Energy in Historic Buildings

The European Union has long prioritized the enhancement of energy efficiency in buildings, aligning with the nZEB (nearly Zero Energy Building) standard, with the ambitious target of achieving Zero Energy Buildings (ZEB) by 2030. This article aims to showcase the use of passive technologies for achieving a Zero Energy Building on a historic building located in Bucharest, with a volumetric design worth emphasizing dating back to the post-war period. This study underscores the challenges architects and engineers encounter in upgrading the energy efficiency of such structures while preserving both their aesthetic coherence and the architectural integrity of the period. Various passive technologies are employed to boost the energy efficiency of the selected building. These include measures such as: thermal bridge reduction, thermal envelope and window details for capturing solar energy and reducing the overheating. The active technologies that remain include ventilation and heating in a small percentage. To assess and quantify the energy efficiency achieved through these interventions, the Passive House Institute’s methodology is adopted. Also, for calculating the solar gain, custom more detailed methods are applied. By showcasing the successful integration of passive technologies in a historic building, this paper contributes to a sustainable architecture and offers practical insights for architects, engineers and stakeholders for achieving ZEB status while respecting the unique characteristics and the heritage of historic structures.