Air and rain tightness of windows.

Tests of airtightness and raintightness of windows have been carried out continuously at the Swedish National Testing Institute since 1977. As many factors such as size, material, method of opening and type of weatherstrip employed can all vary among windows tested, it is not easy to draw conclusions about the influence of any one factor. Test results for each window are also strongly influenced by the workmanship and quality of the individual window. By applying statistical analysis to the results from a large number of tests, it is possible to observe significant differences between the results from different groups of windows.