A structured method to define goals when developing a building energy performance assessment method in a legislative framework

To boost the energy performance of buildings, the EU has established a legislative framework including the Energy Performance of Buildings Directive (EPBD). Through this document, EU state members are incentivized to set up a Building Energy performance Assessment Method (BEAM), tailored to the specific needs of the country. There is no standard definition for the energy performance of a building. Since the options are numerous, it is important for the policymaker to define the goals of their specific BEAM first, before developing the BEAM itself. The definition of these goals is a subjective matter and can differ when asked to different organizations in the building sector. To comprehend the desires and perspectives from each different group, a structured overview of the goals that are important for the specific region is needed. For this paper, a method was developed to provide this structured overview and was tested on the legislative energy performance of buildings (EPB) framework of Flanders, Belgium. The Flemish framework was initiated in 2006 and is still in action today. The method consists of two steps. In the first step, a multi-level tree structure for goal mapping based on the Goal Breakdown Structure (GBS) was developed. The main goal, reducing global warming, is on top of the tree structure, which then subdivides into many sub-goals on different levels. An example of a goal on the lowest level of the structure could be the insulation level of the walls. In the second step, prominent stakeholders in the Flemish building industry, including policymakers, researchers, manufacturers, contractors and building owners, were surveyed to capture their expectations from a BEAM and to query whether the current BEAM corresponds with those expectations. The goal of this survey was to receive qualitative, not quantitative input from the stakeholders. In total, 33 respondents completed the survey. The survey results showed that, in general, the desired goals have not changed substantially compared to the pre-set goals in 2006. Trias Energetica is still the preferred guideline for the decision-making process of the building owner, although its absolute power has decreased slightly and seems to be more prone to the conditions. The current indicator for the overall energy needs (E level) is still strongly preferred, while the recently introduced S level (assessment of the envelope) attracts mixed feelings in terms of usefulness to the entire EPB framework. The overheating indicator receives the most critique for not being accurate enough due to the simplified, single zone BEAM