ABSTRACT
The review of results of laboratory tests carried out for PVC windows shows the considerable differences in the sound reduction index obtained for windows with the same typically used glazing. The sealing is examined as one of the technical factors that can be the cause for such a difference. Two main aspects are considered; the joint between casement and frame as the direct path of sound transmission and the weatherstrips as the supporting element of window sash. In the first case the perfectly tight and untightened windows are considered separately. Reduction of air tightness always causes decrease in sound insulation but the effect is not the same in each investigated case. The weatherstrips are also the assembly elements that affect boundary conditions for the whole casement. Some evidence indicates that the gaskets acting as a casement supporting element influence the sound insulation of a window.
