Renovation of buildings: review of approach and the evaluation of the environmental impact through life cycle assessment

Abstract

Nowadays, renovation of buildings is a general recommendation in order to reduce the operational energy consumption and their emissions associated. Besides, the renovation of buildings allows reusing materials, increasing the building life service and avoiding the deconstruction and new construction impacts. However, it is necessary to be aware that the intervention itself generate an impact (embodied energy, transportation and construction process), and sometimes, energy systems upgrading does not mean a consumption reduction and it also have influence on the city metabolism. The European Union and the Royal Institute of British Architecture have defined strategies in order to reduce the impact associated to buildings through renovations or refurbishments, however, both approaches have differences in their own standpoint. Besides, there are many concepts and terms associated to renovation that do not allow to clarify the objective with a technical and rigorously perspective. Facing the current uncertainties, life cycle assessment technique allows focusing on an already confirmed methodology in order to evaluate the potential environmental impacts associated to the renovation of buildings. While environmental impact on new construction is highly addressed, publication of refurbishment’s environmental impact is lacking in the academic literature. The used materials in construction phase of conventional building accounts for 20% of the total life cycle impact, while the operation energy is around 80%. However, recent researches show how as we design buildings with lower energy consumption the previous balance is levelling, and thus the weight of the materials on the total impact of the building is around 40% compared to 60% of operating energy. Therefore, in this communication are shown the current approaches and concepts in an international context to define a low environmental impact renovation. Firstly, it is proposed a classification of the renovation impacts according to the rebound effect theory. Secondly, it has been done a review of the academic literature that has used the life cycle assessment to evaluate the renovation of buildings, where convergences and divergences has been found between authors. Finally, it concludes highlighting those common perspectives and what fields are needed to develop in order to get a holistic and global approach of the environmental impact of renovation of buildings.