Historic Buildings and Sustainability: The Knowledge Buildings Hold and Passive Design Solutions

The new European directive on energy efficiency will have to be transposed by many countries soon in order to meet decarbonization targets. Its implementation across a continent characterized by buildings of varying age and state of conservation will be most effective if this transposition takes into account the diverse characteristics and values that distinguish these structures. Newly constructed buildings can incorporate effective solutions for reaching these goals. More generally, even ordinary buildings on the outskirts of expanding historic centers are well suited to integrating energy-efficient solutions. For historic buildings, the situation is markedly different. A distinction must be made between structures built before 1945 and those formally classified as cultural heritage, which represent only a small portion of Europe’s building stock. For the latter, unsuitable measures derived from energy efficiency practices developed in other contexts must be avoided. At the same time, these buildings should not be automatically exempted from energy efficiency targets; instead, suitable measures should be identified, including innovative approaches. Of greatest concern, owing to the considerable discretion afforded to individual countries, are the older buildings not formally recognized as cultural heritage. These structures, which account for 25 to 30 percent of the total building stock, form part of Europe’s collective identity and are at risk of significant alteration as a consequence of the climate neutrality targets introduced by the European Union. This raises key questions about safeguarding the values of historic buildings, recognizing the role of structures built before the advent of climate and comfort control systems, and identifying the tools already available to support this transition. This contribution does not aim to propose specific construction practices but rather to clarify the regulatory framework and objectives of energy efficiency in relation to historic buildings, focusing on certain particularly significant aspects. Ongoing projects with Italian stakeholders are closely related to these reflections, and their results may be presented in due course.