"According to the Energy Performance of Buildings Directive (EPBD) Recast, Member States (MS) must set energy performance (EP) requirements “with a view to achieving cost optimal levels”. The term cost optimum means “the energy performance that leads to the lowest cost during the estimated economic lifecycle”. According to Art 2 (14) EPBD Recast, the lifecycle period must be determined by the MS. The purpose is to establish the cost-optimal benchmark for every MS through calculation and using this to assess the current building energy requirements.
The EPBD Recast requires MS to report on the comparison between the minimum energy performance requirements and the calculated cost-optimal levels using the Comparative Methodology Framework provided by the Commission (EPBD Art 5.2, 5.3, 5.4 and Annex III). The report must also include all input data and assumptions made. The Comparative Methodology Framework is accompanied by guidelines from the Commission to enable the MS to:
• Define reference buildings.
• Define energy efficiency measures.
• Assess the final and primary energy needs of the reference buildings and the impact of improvement measures.
• Calculate the cost of the energy efficiency measures by applying the principles of the Com¬parative Methodology Framework
The EPBD Recast does not demand that MS set their minimum performance requirements at levels that are cost-optimal. It does however require reporting how much the requirements differ from cost-optimal levels (implicitly as far as underperformance is concerned). If there are “significant” differences – exceeding 15 % (meaning that the MS allow energy consumptions that are 15 % higher than cost-optimal levels) - MS should justify the differences or plan steps to reduce the difference. Clearly, this first requires the calculation of a cost-optimal requirement.
Cost-effectiveness and cost-optimality can be considered from several different perspectives, each of which will usually provide a different result. We summarise the two main important perspectives:
• Of the society as a whole: the “macro” economic perspective.
• Of the idealised end-users: the “micro” economic perspective.
Both perspectives serves a different purpose and MS will, no doubt, assign a different importance to each of them when setting requirements.
This Community offers the possibility to exchange knowledge about the Comparative Framework Methodology for calculating cost-optimal levels of minimum energy performance requirements for buildings and building elements. Furthermore the Community gives the possibility to gain insight in early experiences from other MS who have carried out a cost-optimality study on their national regulations and join the discussion on the future of setting EP requirements in Europe.
Join the Community on Cost-Optimal procedures.