Highly insulated window glazing

The paper is introduced by a short survey of heat-transfer processes through a double-glazed window system. Network calculations show the advantage of a double-glazed window including at least one heat-reflecting filter and an IR-trans-parent foil. In the optimum system with one foil, the UL value is slightly below 1 W/m2K. Several insulating glazing systems with air and with krypton filling are compared, and all UL values are calculated. the application of an IR-transparent foil to a solar collector is discussed, and the measured top losses are given.