In order to facilitate large-scale energy optimisation for all buildings until 2030 (SFOE objectives), the ProRen project aims to create a framework to facilitate: an understanding of the entire renovation process, the development of a global approach to renovation that takes into account skill mismatches between actors and an "intelligent" data collection and processing method. This framework allows the setting up of inter-institutional projects in the future development of the unifying theme "Interventions on existing buildings".
The improvement of energy performance of buildings has been one of the forefront issues in Switzerland for the last ten years. In order to tackle this challenge, numerous bodies, strategies, instruments, labels, standards, and norms have been developed and implemented. A lot of attention has been paid for a long time to new buildings, but the recent 2050 vision by the SFOE (Swiss Federal Office of Energy), marks a turning point by placing renovation of old buildings as a priority to achieve the goals set for the 2050 energy strategy. With this in mind, the SFOE sets ambitious goals, such as demonstrating the cost-effectiveness and the possibility of performing energy efficiency at a large scale for all big buildings (2020–2025), even for all buildings until 2030.
In spite of these measures and the political will, energy consumption of the Swiss building stock, largely exceeds the 100 TWh objectives. The problem to explain this paradox lies in the existing gaps between the legal framework specific to the construction sector, energy-related renovations, reality on site, requirements of an efficient renovation process, and the expertise of different stakeholders, like for instance, between a CECB (certificat énergétique cantonal des bâtiments) expert, who has an energy-oriented vision, but no construction skills, and the artisans, who follow their suppliers’ requirements but lack the theoretical knowledge to be able to assess the merits of standardized solutions on a case-by-case basis. Several different issues arise from this problem. We all know that planning is rare in the renovation field, that it is carried out by artisans based on brief energy assessments performed by CECB experts, and that the breakdown of charges between homeowners and tenants is not clear.
The first issue ProRen should therefore tackle is the understanding of the whole process, from the assessment of the existing building, to the renovation, and finally the operation of the building. The eREN project has shown that the energy performance through the renovation process should not be considered as a separate element from all others, i.e., increase of the value in use, changes in building usage, aesthetics, static, protection against natural disasters, protection of historic buildings, building physics, financial viability, etc. The second issue to be tackled would be the development of a global renovation approach involving specialists from different domains (technical installations, structure, envelope, etc.). The eREN project has also identified a special renovation feature that has major implications on the feasibility and reliability of the process: the thorough knowledge of the existing building. A third issue stems from here, the identification of guidelines for a « smart » data collection and process - work that prepares the future integration of the « renovation » issue in a BIM process.