Superwindow
According to Aris Yi, much of the Rocky Mountain Institute’s performance can be attributed to its advanced windows. 1 While the high performance windows have a steeper price tag than standard off-the-shelf windows, they are much more energy efficient and can save enormously over a greater period of time. While the original glazing was argon filled and used one spectrally selective surface, later improvements were given a second selective surface and were filled with krypton, which insulates twice as well as air. 2 These extra coatings lose only 8% as much heat as a single pane of glass, and manage to allow 52% of visible light to pass through. 3 In the superwindows, traditional aluminum spacers around the edge condition of the window were replaced with steel, which cut conductivity by over 80%, while in today’s units, interior glass-to-glass thermal bridges were replaced with polyester spacers, and many sashes are stuffed with fiberglass superinsulating nanogel. 4 As a definition, however, superwindow does not necessitate a strict performance threshold or quality, it is simply a term which was coined for high-performance windows, which means the term should be used and understood with some amount of discretion; that is, a superwindow in one building may not perform as well as a superwindow in another.