Window structure

Thermal break window structure including a generally rectangular outer frame portion, a generally rectangular inner frame portion and an insulating member positioned between the inner and outer frame portions and cooperable therewith for rigidly securing the frame portions together into a prime window frame without contact between the inner and outer frame portions, said thermal break window structure further including an inner window and an outer window each including corresponding movable sash and further including a sash coupler extending between the inner and outer movable sash whereby the movable sash may be selectively moved together, wherein the insulating member has a cross section including an elongated central portion extending transversely of the plane of the window structure, the insulating member extends through the frame parallel to the plane of the window only in offset locations separated by the extent of the elongated central portion of the insulating member and defined by the frame portions and wherein the insulating member includes an H-shaped portion at both ends of the central portion having opposite parallel parts in common with the central portion of the insulating member and the frame members have a cross section including a pair of parallel spaced apart parts one of which is longer than the other, the longer of which parts of the frame members extend on opposite sides of the central portion of the insulating member and between the parallel parts of the H-shaped portions of the insulating member at the inner ends thereof.