The significance of windows is stressed, and technical conditions for their processing, as defined in relevant technical regulations, are presented, regardless of material they are made of. The proposal is given for the selection of the most appropriate window depending on the type of material, and advantages and deficiencies of windows are presented. The results of laboratory testing conducted to define technical properties of wooden, aluminium and PVC windows are given. Test results are analyzed in order to define quality of windows before their installation.

Key words:
window, technical conditions, testing, selection, advantages, deficiencies, installation