In modern well insulated buildings U-values for walls of 0.3 W/(m2 K) or even below can be realized. In such buildings, glazings with typical U-values of 1.0 W/(m2 K) or higher are thermal weak spots in the façade. One attractive possibility to essentially improve the insulation properties of a glazing is to evacuate the space between the glass panes. This virtually eliminates heat transport due to conduction and convection of the filling gas. The glass panes can be prevented from collapsing by using a matrix of spacers (see Figure 1). Evacuated glazings are already available as a commercial product , however have U-values of 1.1 W/(m2 K) or higher.