Overview on life cycle methodologies and economic feasibility for nZEBs

The recast Directive on the energy performance of buildings (EPBD) stipulates that by 2020 all new buildings constructed within the European Union after 2020 should reach nearly zero-energy levels. This means that in less than one decade, all new buildings will demonstrate very high energy performance and their reduced or very low energy needs will be significantly covered by renewable energy sources. Such change is affecting both the nature of the built environment as well the actual method of designing and constructing a facility. The economic feasibility to realize a sustainable construction need to have a clear support by adequate analyses connected to the energy consumption and consequently to the new target reductions in greenhouse gas emissions for buildings. Life Cycle Methodologies (LCMs) are currently not considered in details on the EPBD recast, but according also to recent researches, they might be important tasks in a future recast. The paper analyses this challenge providing an overview on the main LCMs to individuate principles, limitations and implications of these approaches to design a Nearly Zero Energy Building (nZEB).