Within the context of an energy performance regulation, it is essential to take the transmission losses
into account. If building details are not well designed or carried out, thermal bridges can substantially increase the transmission losses. Though, the physical principles for evaluating thermal bridges are well known and covered by European standards. However, the practical application of these calculation rules is not that evident and may be very time consuming. Within the framework of the Flemish Energy Performance Regulation, a strict scheme for compliance is adopted, in which incorrect performances are linked to financial fines. Such framework for compliance check requires transparent and reasonable procedures for handling thermal bridges. In the beginning of 2006, such procedures were not available yet and, therefore, it will only be mandatory to take into account thermal bridges for building permits requested after January 2008. In the framework of the TETRA IDEE project, a concept for handling thermal bridges is developed and should be finalised in December 2006.