AIMING AT A PRACTICAL TOOL ASSESSING RESIDENTIAL BUILDING REFURBISHMENT PROJECT USING LCA AND LCC: THE BAT-ECO2 PROJECT

Considering the actual French building stock, 65% of dwellings were constructed before 1975, without any thermal regulation. This share corresponds to an average energy consumption of 300 kWhPE/(m2.yr). The French law for... [ view full abstract ]

Considering the actual French building stock, 65% of dwellings were constructed before 1975, without any thermal regulation. This share corresponds to an average energy consumption of 300 kWh_PE/(m².yr). The French law for energetic transition stipulates a French environmental target of 75% decrease of GHG emissions between 1990 and 2050. Thus, in order to achieve this target, a national program has been implemented to reduce the primary energy consumption contribution of the building sector. A big share of the primary energy consumption reduction is to be related to refurbishment of the fore mentioned 65% of dwellings. Thus, more and more attention is paid to the refurbishment operations and to the resulting life cycle of refurbished building in terms of environment and of finance. To assess the life cycle environmental impacts and cost, Life Cycle Assessment (LCA), and Life Cycle Cost (LCC) are two acknowledged methods based on ISO standards. However, there are still crucial methodological discussions about how to implement these methods and about the way to combine the corresponding assessment results. In that context, several French actors of Hauts de France and a Canadian Research Center teamed up on the Bat-Eco2 research project aiming at creating a simplified decision-support tool for preliminary design phase of refurbishment studies. The project partners are Université d’Artois, Université de Lille 1, CD2E (a public agency), CIRAIG (an international reference center on life cycle assessment), CROA (an architect association), NJC Économie (a firm specialized in construction economics) and Maisons & Cité Soginorpa (the social landlord is foreseen as the main end user of the tool). The tool will consider the combination of potential environmental impacts together with economic indicators for the assessment of existing detached single-family houses. One of the original aspects of the future tool will correspond to the convenience and ease of use through a user-friendly display of results. To develop such a tool, the research project first stage focused on the LCA methodology based on existing standards, guidelines, case studies and tools, whilst keeping in mind to elaborate a decision-support tool that is user-friendly for a non-expert. In order to know which materials, processes and life cycle steps to take into account in this tool, an extended LCA was performed and LCC study is under work on the main renovation schemes that the social landlord intends to carry out. From these studies, the hotspots are to be drawn and the tool main technical specifications are to be built up. According to the refurbished building LCA results, the hotspots are products’ stage, energy consumption (use stage) and replacements (use stage). The tool will be implemented based on those hotspots.