Abstract: An extruded aluminum window is provided with outer frame members for fastening to the building and inner frame members for fastening and holding one or more glass panes. The frames are provided with a sealing system which while allowing pressure equalization prevents air and moisture from passing into the interior of the structure when the window is closed. The sealing system includes an external water deterrent and a pair of internal sealing members with the frame between the external deterrent and the internal sealing members having a water barrier formed with a plurality of serrations each in a plane parallel to the frames. The sill of the outer window frame is provided with internal and external upwardly extending legs, and a raised central portion which joins the external leg in a recessed gutter to drain water out through slots in the external leg. In one embodiment the window can pivot a full 180.degree.