Evaluating Thermal Insulation of Light Façade Walls

For practical purposes, the mean thermal transmittance of a light façade wall may be adequately calculated from the values of the individual elements (frames, panels and glazings), considering their individual area ratios. These values can be determined experimentally, by means of numerical calculations or by using the graphs presented in this paper. The correct determination of the thermal transmittance of opaque panels is essential. The edge can increase the total heat loss by a factor of 4 compared to the heat loss of the central area of the panel. For ventilated façades, the influence of the ties on thermal transmittance should be considered. For glazed façade areas, including frames, corrections using the linear thermal transmittances at the edge will provide sufficiently accurate mean values for practical purposes.