# The Evaluation of Historic Building Energy Retrofit Projects through the Life Cycle Assessment
Among all, the life cycle assessment (LCA) is an evaluation tool capable of assessing the CO\({}_{2}\) emissions and other greenhouse gases emissions during the whole life cycle of a building or product. Life cycle assessment is considered an evaluation tool capable of supporting sustainable design. The rules for performing a life cycle assessment are defined by specific standards [16]. The most important standards for building life cycle assessment are ISO 14040 and ISO 14044. Moreover, construction works' specific standards include EN 15978 (LCA standard for construction projects), ISO 21929-1, and ISO 21931-1 [6]. Environmental product declaration standards are also applied in the LCA software used (One-Click LCA) including ISO 14025, EN 15804 (EPD data), EN 15942 (EPD format), and ISO 21930 [9]. This tool is very important in the ex-ante phase of the design because it focuses on performance estimation, criteria weighting, and design alternatives generation. There are many studies in the scientific literature that explore LCA's enormous potential as evaluation method. There are some researchers, like [PERSON] et al. (2020), that propose the integration of LCA with the life cycle inventory (LCI) and the life cycle impact assessment (LCIA) to assess a building's energy performance in terms of the direct and indirect use of energy (electric use for heating and cooling, water use, treatment of waste water, and use of natural gas). This integration of assessment methods is capable of assisting designers in making future design choices to improve the performance of the building [17]. [PERSON] et al. (2021) indicate that it is necessary to consider assessment methodologies based on cost-effective parameters (CEP) to support decision making in the selection of renovation strategies to reach the nearly zero energy building (NZEB) target of the European Union standard for the building's renovation [18]. In this regard, the focus of this study was the \"energy renovation of historic buildings\" through the use of innovative materials and technologies. The existing building stock in Europe represents 80-90% of all buildings that will exist in 2050 [11], while buildings are responsible 40% of the energy consumed in Europe [19]. The \"New European Bauhaus\" mentions that the renovation of cultural heritage is able to contribute to the green transition (according to the New Green Deal), through the energy retrofitting of the historic buildings. Moreover, the reuse of cultural heritage is able to generate greater social inclusion, through the valorization of crafts and creative industries [20]. The Council of Europe's Faro Framework Convention on the Value of Cultural Heritage for Society should be used to root the green transition in the European values of cultural diversity, human rights, and participatory democracy [20]. The European Standard EN 16883:2017 provides guidelines for sustainably improving the energy performance of historic buildings, e.g., historically, architecturally, or culturally valuable buildings, while respecting their heritage significance. It acknowledges the importance of assessing the whole life cycle of a building by stating that \"historic buildings should be sustained by respecting the existing materials and construction, discouraging the removal or replacement of materials /.../ which require reinvestment of resources and energy with additional carbon emissions\" [10]. Therefore, the aim of this paper was to explore how, through the use of innovative materials for the energy renovation of historic buildings (in particular, hep materials), it is possible to contribute to the green transition, thanks to the reduction of environmental impacts, in terms of CO\({}_{2}\) emissions, in the entire building life cycle. In this perspective, the life cycle assessment is a fundamental tool, able to compare different solutions in the ex-ante planning design.