If the bottom of the window is 80cm or less from the floor you need safety glass. Therefore most windows are much further from the floor than that tube can reach. We also have very few sliding windows that allow such neat finish. A lot open at the top. Many turn left or right and are half the size of a door (because there is no AC) Running a crappy tiny portable single hose AC with the window open doesn't do much. Extra fun if you have roller shutters (for shade) with windows that open outwards.