Lack of regulation on the energy efficiency in Serbia in terms of the assessment of the impact of thermal bridges

As one of the aspects of sustainable architecture, the energy efficiency of buildings has largely come to life and has found its practical application in modem construction practice. Active action towards the achievement of the adequate energy performance of buildings implies the creation of appropriate regulations, providing basic guidelines for securing energy efficiency in the design and construction of buildings. In that sense, with a dozen years of delay in relation to the introduction of the EPBD, Serbia has adopted its legal regulations regarding energy efficiency in buildings, being in force since 2012. Respecting the basic guidelines of the original directive, the regulations in Serbia were the subject of major changes in relation to the previous ones, making a major shift in the boundaries of the relevant parameters and the basic methodology of calculating the energy performance of buildings. However, in practice, it has been shown that some of the factors that are important for the design and energy behaviour of the buildings have been treated inadequately. This particularly refers to the problem of thermal bridges, whose impact on the overall energy performance of the buildings is too simplified. Consequently, depending on the complexity of the building, the prescribed calculation methodology often yields significantly fewer energy needs than they actually are. By taking the view that the influence of thermal bridges, regardless of their type and character, is treated as an arbitrary magnification of surface transmission loss in the function of magnifying the surface of the thermal envelope, the real impact of both linear and point heat losses is neglected. While the issue of an adequate calculation of linear losses is directly related to the way of designing the building, that is, to the conception of details, the question of the impact of point losses is a consequence of the structure of thermal envelope elements. The paper presents two types of critical cases of thermal bridges: the treatment of linear thermal bridges for which research has shown that their influence can significantly exceed those envisaged by the current rulebook, and the influence of point heat bridges, as seen in the specific case of ventilated facades in which this problem is present.