Energy retrofit of heritage buildings: A literature review on adopted solutions for balancing efficiency and heritage

The energy retrofit of heritage buildings poses a complex challenge that requires balancing energy efficiency objectives with the need to preserve architectural, cultural, and historical values. This review offers a comprehensive analysis of scientific literature focused on retrofit interventions in heritage buildings, with particular attention to the Italian context, which is among the most active globally in this field. Based on a systematic methodology, following PRISMA principles, 34 relevant articles published between 2014 and 2024 were selected and analysed. The studies were classified by disciplinary approach, either single-discipline or multidisciplinary, and by building use typology (residential, educational, workplace, cultural/public, or not-case-specific). The review identifies the most commonly adopted retrofit solutions, highlights the added value of interdisciplinary strategies, and evaluates the compatibility of these interventions with conservation requirements. Existing research gaps are also discussed, offering suggestions for future investigation. Ultimately, this work aims to support professionals and decision-makers in developing retrofit methodologies that are both technically sound and respectful of the historic identity of built heritage.