Life cycle approaches for the green retrofitting of existent buildings

The building sector has a key role in the fight against the climate change, since it is responsible of the largest share of energy consumption and CO2 emissions both at global and at European levels. In Europe, the existing building stock represents a huge problem since its almost entire share is energy inefficient. Therefore, a green retrofit action is needed, that is not only meeting the minimum energy performance requirements and being financially beneficial to the building owners, but that also has a low environmental impact. The aim of this Master's Degree thesis is to identify how the researchers have been figuring out a methodology for the economic evaluation of a green retrofit scenario in a life cycle perspective in the European context. The work is structured into four chapters related to the main macro research areas. The first one deals with a theoretical framework about the economic foundation of the sustainable thinking and it introduces the models of Circular Economy (CE) and Green Economy (GE), in which the green retrofitting can be identified. Then, the building energy performance regulation is defined into an European regulatory context in which the main strategies and legislation adopted in the construction sector are described, with a specific attention to the growing focus on the existing buildings. In addition, the Italian documentation related to the building energy performance is reported and analysed by highlighting the most innovative developed tools. The third chapter introduces the methodological context of the Life Cycle Thinking (LCT), an approach that considers all the life cycle phases of a building, or a building component, and its related activities, and two derived techniques: the Life Cycle Assessment (LCA) and the Life Cycle Cost Analysis (LCCA) or Life Cycle Costing (LCC). The former is a method to assess the environmental impact of a product, or a building. The latter is a technique for the economic evaluation of a new or an existing asset which takes into account both immediate and long-term costs and benefits. LCCA is at the base of the literature selection presented in the fourth chapter, whose focus has been the application of the Life Cycle Cost Analysis for the economic evaluation of retrofit projects and the development of an integration between the economic and the environmental impact analysis, for the assessment of the most sustainable refurbishment scenario among alternative retrofit strategies. The selection process represents a first innovative aspects of this thesis research. Moreover, the resulted limited number of articles and the adoption of a different methodological application in each of them have allowed the implementation of a new literature analysis method. Finally, the selected articles are analysed in order to identify the different approaches in which the economic and environmental analysis are performed, even through integrated applications.