Abstract: An automatic aeration window comprises a movable frame with three parallel window panes separated by gaps, a first lower passage and a second lower passage at the bottom of the window and an upper intermediate passage connecting the two at the top of the mobile frame. In order to enable a light-weight construction of the movable window frame, the first lower passage, connected to an external opening on the outer face of the window and to a first lower opening, is provided in the fixed frame of the window. A closing flap controlled by a puller is also mounted in the fixed window frame, while the second lower passage preferably also passes through this fixed frame. The invention may be used in windows to provide aeration and good acoustic and thermal insulation.