The ZEB4ZEN project was implemented in four historic neighborhoods across Central Europe: Karlovac, Palmanova, Zamość, and Quedlinburg. The main challenge of the ZEB4ZEN project was to develop zero-emission neighborhoods that integrated historic buildings with modern, energy-efficient technologies and renewable energy systems, reducing emissions while preserving cultural heritage. This required innovative solutions and collaboration across multiple sectors to achieve sustainability and energy efficiency at the neighborhood level. Historic neighborhoods faced the dual challenge of preserving their cultural heritage while improving energy efficiency and reducing carbon emissions.

The core problem addressed by the project was the challenge of retrofitting historic buildings to achieve near-zero energy emissions while preserving their cultural and architectural heritage. Traditional renovation approaches often treated buildings in isolation, missing opportunities for energy optimization at the neighborhood level and synergies between buildings. Additionally, a common misconception was that historic buildings should not be equipped with new energy-efficient technologies. The project aimed to overcome these barriers by identifying and exploiting solutions that modernized historic centers while safeguarding their historical value.

The main idea behind the ZEB4ZEN project was to develop a comprehensive methodology and define action plans for achieving zero-emission neighborhoods (ZEN) by integrating modern energy-efficient technologies into historic urban areas. The project focused on reducing energy demand and carbon emissions from buildings and transportation—sectors responsible for over half of EU emissions—by transitioning to highly efficient, electricity-based systems. It also explored how interconnected neighborhood buildings could actively participate in the electricity market, benefiting both residents and the energy system. By leveraging the experience gained from pilot activities and investments in neighborhoods rich in historic buildings, ZEB4ZEN developed a structured methodology for defining scenarios to achieve ZEN. This methodology was designed to be replicable across different regions and was presented to a broader audience using virtual reality technology, demonstrating that historic buildings could be preserved and modernized to meet future energy standards and sustainability goals.

Our approach began with a thorough exchange of experiences and knowledge among project partners, fostering innovative solutions. First, we conducted energy audits and data collection to assess the potential of each neighborhood for near-zero energy consumption. Next, we implemented energy efficiency and renewable energy measures, such as advanced insulation techniques, solar installations, and digital tools like virtual reality for planning. Finally, we developed structured action plans and a clear methodology applicable across various districts to guide cities toward achieving zero-emission status while respecting their cultural heritage.

ZEB4ZEN demonstrated that the transition towards zero-emission neighbourhoods is possible even in historic urban areas where energy ambitions must be balanced with cultural heritage protection. By transforming experience from four pilot neighbourhoods into transferable methodologies, action plans, digital tools and practical guidance, the project provided cities and regions with a foundation for planning and replicating sustainable energy solutions beyond the pilot areas. ZEB4ZEN showed that preserving historic identity and advancing the energy transition can go hand in hand, supporting more sustainable and climate-neutral historic neighbourhoods across Central Europe.