The thermal behaviour of glass panes strongly depends on the environmental and constructive conditions and is insufficiently examined in terms of a safety design. Planners lack normative principles and experiences in order to determine the thermal behaviour of glass with all occurring influences. Increasing requirements in terms of energy efficiency and user comfort lead to complex acade elements, which often exist of triple insulating glass units with thermal or solar control glasses and additional shading elements. The composition of materials and the glass built-up influence the thermal behaviour of the single glass panes. A disadvantageous combination can cause high temperature differences and consequently critical thermal stresses in the single glass panes. Thus, an insufficient dimensioning of the glass panes can lead to a thermal reakage of the glass. As a contribution to the subject, the thermal behaviour of triple insulating glass units was examined. With the parameters functional oatings, frame material and a shading element, a small experimental test series was carried out to gather information about the effect on the thermal behaviour under constant radiation. The specimen were provided with temperature sensors on each glass pane to measure the temperatures of the glass edges and surface. The paper presents the current situation in the design approaches, describes the test set-up in the laboratory hall, evaluates, and rates the measured data of triple insulating glass units.