Since ZEB4ZEN focuses on pilot activities in the historic cores of cities, where green technologies and digital solutions are carefully combined with heritage conservation requirements, special attention is given to balancing energy performance improvements with the protection of architectural and visual identity. As part of the project activities, a live meeting was held in Karlovac at the City Hall. During the meeting, the ZEB4ZEN project was presented, followed by an in-depth discussion on approaches to renovating historic buildings and the possibilities of integrating energy efficiency measures without compromising their visual and cultural value. In particular, the project team from the Energy Institute Hrvoje Požar presented the activities and preliminary results of Work Package 3, including the analysis of the energy potential of cultural heritage buildings in Karlovac’s historic core and their role in achieving Zero Energy Neighbourhood (ZEN) objectives. The development of a ZEB4ZEN digital platform, planned as a GIS-based application providing building-level data, conservation constraints, and guidance for energy efficiency measures, was also announced as a key upcoming project output. Conservators highlighted numerous practical challenges, particularly those related to the lack of standardised renovation procedures and the need for a conservation database for buildings located in cultural heritage districts, which is a national program under development and includes the Zvijezda district in Karlovac. This database aims to systematically collect and structure information on the conservation status, typologies and key characteristics of protected buildings in the City of Karlovac. Once established, it will significantly improve access to clear and reliable information for property owners and project designers, helping them better understand the scope of interventions applicable for individual buildings. The discussion confirmed a strong alignment between ZEB4ZEN district level methodology for decarbonisation of energy supply and the ongoing development of the district level conservation database, creating opportunities for future data sharing and coordination between the two systems.
