Influence of glazing size on energy efficiency of timber-frame buildings

Competitive fields of residential building are aware that today’s prefabricated timber building is extremely highly valuated and is capable of fulfilling all of the demands from our society and from the environment that we live in. Additionally, due to strict energy requirements, the tendency to use a higher share of glass wall surfaces occurs worldwide. Therefore, the aim of this research is to investigate an alternative solution by using a glass sheathing material instead of classical wood-based or fibre-plaster sheathing boards in timber-framed walls as the main load-bearing elements in prefabricated timber-framed buildings with a special focus on the annual energy demand behaviour for heating and cooling. The research is based on a case study of a two-storey house with a prefabricated timber-frame structural system and its parametric analysis of an increased-proportion-of-the-glazing-surfaces impact, taking the climate data for Ljubljana into consideration. The analysis was carried out on different exterior timber-frame wall elements having different thermal properties, while the rest of the parameters, such as the ground plan of the model as well as the active systems, roof and floor slab assemblies remain constant. The graphical presentation includes a function curve showing the annual energy demand for heating and cooling depending on the proportion of the glazing area in relation to the total surface area of the south-oriented façade. The comparative analysis results can nevertheless serve as a good frame of reference to civil engineers and architects in an approximate estimation of energy losses accompanying the different positioning and proportion of glazing surfaces while using various prefabricated timber-frame wall elements as well as serving some basic principles in the energy refurbishment of old timber-frame buildings.

► Determination of a relation between the Uwall-value, glazing size and energy demand.
► Determination of the optimal glazing size for contemporary timber wall elements.
► Presentation of the renovation method for the old timber-frame housing.
► Findings important for the renovation principles of the old timber-frame housing.
► Directions for further research related to the use of a double-glazing.