Energy performance of facades and buildings - IEA as support for the European directive?
Within IEA Task27 the topic of energy performance of advanced windows and facades was taken up in an international cooperation project. Different approaches throughout the various member countries were presented and discussed with the aim to develop the methodologies further and to harmonize the approaches. This work seemed to fit to the European Energy Performance Directive (EBPD) published in January 2003 as 2002/92/EG, where the topic of a certification of the whole building - building structure and technical building services is being taken up. The directive works on the subsidiarity principle with a harmonised European structure and local national implementations. A methodology for calculating integrated energy performance EP is needed, which can be used for specifiying the minimum requirements on EP of new buildings and for large existing buildings under major renovations, and for energy certification. The EPD shall be fully implemented in January 2006 and due to the tight time frame only little time was left to develop (inter)national integrated methods and certification schemes. In the following paper the general ideas within the IEA group are presented. These ideas could partially be transported into the national and European standardization groups through individual members, but many other issues had to be respected as well. Two basic approaches were identified which have different advantages and disadvantages. One is the so-called component performance assessment methodology (CPAM) where the performance of the façade is characterized with physical quantities associated alone with the building element. The second approach is the building performance assessment methodology, where the performance is characterized indirectly via building performance indicators, i.e. the components influence on overall building performance is the meter stick. Both methodologies and some aspects of the discussion within the standardisation organizations on the way to an European Building Performance standard will be described in the paper.