Pellon adjustable sash window allows excellent adjustment options for supply of replacement air in both summer and winter conditions. Translucent cellular panel allows excellent light penetration, so the large window surface brings additional luminosity into the production building. Due to the channel structure of the cellular panel, the panels insulate heat very well. The material is a safe alternative for window use, because there is no risk of breaking glass. The cellular panels can be adjusted either manually or by automatic control through a weather station.