Abstract: A window, in particular for mounting in an inclined roof surface, comprising a frame structure and a relative thereto openable sash structure with an insulating pane (6), the frame and the sash structures comprising top, bottom and side members (21-24) in the form of solid profiles which are for the major part made from a thermally well insulating material. For providing a good heat-transmission from the interior side of the sash structure to border areas of the insulating pane a passive heat bridge has been established at least in the areas (30, 31) around the corners of the sash bottom member (21) and the adjacent side members (24), said heat bridge being of a well heat-conducting material and established in connection with or through said bottom and side members (23, 24) of the sash structure.