High performance thermal insulating low-emissivity glass, with a very thin transparent heat-reflecting hard metal oxide coating sprayed at a temperature of +/- 600 graden Celsius on the float glass ribbon as it leaves the furnace. The coating, which penetrates into the glass surface, is remarkably strong and durable. Planibel K Glass can be used in single panes, but is generally assembled into high performance thermal insulating double glazing, with the coating located at position 3 (on the inner glass pane, inside the double glazing).