While the Energy Performance of Buildings Directive (EPBD) requires that from 2020 all new buildings are nearly Zero-Energy Buildings (nZEBs), the proposed definition leaves a number of uncertainties, especially regarding the level of ambition for such buildings in terms of energy consumption and CO₂ emissions. The aim of this study is to support the implementation of the recast EPBD by developing a sustainable, effective and a practical definition for nearly Zero-Energy Buildings.

This report strives to contribute to reaching a common understanding of nZEBs by:

• Providing a starting point for an nZEB definition by analysing existing concepts and initiatives;
• Outlining the main challenges and potential solutions for an nZEB definition;
• Compiling a possible set of principles for nZEBs;
• Applying such principles on reference buildings and assessing related effects;
• Depicting related technological, financial and policy implications at EU level; and
• Giving an outlook on necessary further steps towards a successful implementation of nZEBs.