The recast of the Energy Performance of Buildings Directive (EPBD, 2010/31/EU) requires Member States to introduce minimum energy performance requirements for buildings, building elements and technical building systems and set these requirements based on a cost-optimal methodology. This methodology introduces – for the very first time – the prerequisite to consider the global lifetime costs of buildings to shape their future energy performance requirements.

The methodology to calculate cost-optimal levels of minimum energy performance for buildings and building elements was established in the Cost-Optimality Commission Delegated Regulation (2010/31/EU), while an additional guidance document on how to implement the methodology at national level was published by the EU Commission in April 2012. Nevertheless, the EU regulation and guidelines leave a very large degree of flexibility for Member States, regarding the selection of input data for the calculation, the reference buildings selection, energy costs, etc. Convinced that Member States would benefit from additional guidance on the cost-optimality process and on how to use the methodology relating to nearly Zero-Energy Buildings (nZEB) requirements and long-term climate goals, with his report BPIE intends to provide practical examples on how to effectively implement the cost-optimal methodology at national level. The main goal is to evaluate the implications of different critical parameters, as well as to share good practices across EU countries.

Three case studies were delivered with the support of consultants from Austria (e-sieben), Germany (IWU) and Poland (BuildDesk), focusing on cost-optimal calculations for multi-family and / or single-family buildings. The report and case studies demonstrate how ambitious yet affordable cost-optimal energy performance requirements for buildings can be, and how the transition towards nearly Zero-Energy Buildings (nZEBs) can be supported.