Vacuum Insulating Glass. Past, Present and Prognosis

This paper reviews the history and current status of Vacuum Insulating Glass (VIG), and discusses future possibilities for this technology. VIG was first described in a 1913 patent. Despite several attempts and many patents over the intervening years, the first thermally insulating experimental VIG samples were not made until 1988, at the University of Sydney. In 1994, the University and Nippon Sheet Glass (NSG Group) commenced a collaboration on VIG that is still continuing. The first commercial VIG product, Spacia, was launched by NSG Group in 1996. Several million Spacia units have now been manufactured, and have shown excellent reliability in many types of building. Current VIG designs using annealed glass can have centre-of-glazing U values below 0.6 W m -2 K -1 in a structure less than 10 mm thick. VIGs are being used in hybrid glazings and laminated assemblies. Several organisations are undertaking VIG-related research. Other commercial VIG products are in the market or under development. VIG Standards are in preparation. There is scope for significant improvements in the technology. Future possibilities include tempered glass VIGs, triple glass VIGs, alternative designs of edge seal, pillars and low E coatings, and advanced manufacturing methods.