In conventional construction, the windows of a building are usually the weakest part of the thermal envelope. Well insulated walls can be built with a number of different kinds of construction and a variety of insulation materials. But windows, particularly ones that the inhabitants of the building can see through, are hard to make as efficient as the walls they are installed in. But prototype windows from Super Windows have astonishing thermal resistance as well as good visibility.
These windows are ridiculously efficient. As noted on Jetson Green, "The inventive window makes it possible to achieve European U-values of 0.15 W/m2K, or the U.S. equivalent of R38 (R = 1/(.15/5.678))." For comparison, the insulation value of batt insulation in a 2 x 4 stud wall has a U.S. R-value of just R-11. That makes the windows more than 3 times as effective an insulator than the walls are.
These windows are only developmental at this point. Even if they were in commercial production and affordable, they would not be easily retrofit into many homes because these windows are about 160mm (more than 6 inches) thick. The windows are made with two panes of glass and ten (!) intervening film layers that provide this astonishing level of performance.
For high performance buildings such as highly insulated and extremely low energy consuming Passive House designs, these windows may be especially desirable. Even more moderated versions of these windows could provide more efficient windows by adapting lessons from these prototype designs.
image: Super Windows
via: Jetson Green
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