Integrating embodied impact into the context of EPBD recast: An assessment on the cost-optimal levels of nZEBs

Towards the zero energy and emission future, near Zero Energy Buildings (nZEBs) lead the path for the building construction sector. European legislation provides normative provisions for the definition of nZEBs and their cost-optimal levels within the context of EPBD recast and Delegated Regulation No.244 (2012). However, that same framework unilaterally assesses the building's impact and considers only the emissions from the operational phase. The present study is a first approach of integrating embodied impact into the context of EPBD recast for the cost-optimal levels of nZEBs, an option provided by its accompanying guidelines. The proposed two-step assessment combines the LCA, LCCA and Energy analysis on the Greek nZEB case study. An extended sensitivity analysis regarding climatic, design and monetary parameters, correlates the effect of embodied impact with the transposition of the cost-optimal levels to building variants with lower material intensity. That same transposition highlights an increase in the primary energy of the cost-optimal level between 0.00 kWh/m(2).year and 3.57 kWh/m(2).year and a decrease in the share of embodied to the total life cycle emissions and energy between 0.61% and 2.36% and 0.78% and 2.82%% respectively. The effect fades in the total sensitivity analysis scale, where it is located only within the range of results that follow the current energy efficiency regulations' calculations. Results validate the outcome of a previous companion case study, while both indicate the need for further analysis in order to assess the aspects of nZEBs which are subject of variable definitions across the EU member states. (C) 2020 Elsevier B.V. All rights reserved.