Windows add beauty and architectural interest to a building in addition to their obvious functional roles of illuminating and optionally venting the interior, as well as providing views and alternative means of egress to the exterior. But windows have always been a weak spot from an energy efficiency standpoint.
Two scientists in Hannover, Germany; in association with Superwindows, showcased a 12x ”glazed” window prototype at the recent Passive House Conference; according to an article in Jetson Green. Two prototypes, both 160 mm (appx 6 ¼”) thick, use 2 panes of glass on the interior and exterior and have aerogel insulation in between to improve the R-value and weight (similar to a triple-glazed window) without compromising on visual quality. Light transmittance and weight are comparable to that of a modern European triple pane (three glass panes) window.
The Invis160stack has aerogel sheets parallel to the glass, reaching an R-38 ; while the Invis160tweed has aerogel sheets at 45deg angles to the glass, allowing it to achieve a phenomenal R-113 ! (Most North American window manufacturers windows score about R-3.3)
There is, of course a lot of work to be done before these windows become commercially available and affordable, but it is interesting to know that we can may soon see super performing windows without changing drastically the definition of the term as we know it today.
Here’s a link to the original article.