Low-E is a 5 layer coating 4000 atoms thick that can be put onto glass or plastic. Because the coating is so thin, it is invisible, and it costs only 3 cents per square foot (€0.2 per square meter), less than opaque insulations. Even though this coating is a hundred times thinner than paper, it can insulate as well as an inch of plastic foam when it is used with dead air spaces, as in double-paned windows, tripling their insulating value. The materials it is made from and their structures are carefully designed so the coating reflects heat. That is to say, it reflects the invisible thermal radiation that transfers heat, as shown in Figure 1. Low-E was selected by Popular Science as one of the 100 most important inventions in the last 100 years. (1)
(1) November, 1999, p11
Cloud Gel is a unique glazing material that transmits 90% of sunlight when heat or illumination are needed, but by turning opaque white, reflects 90% of sunlight when a room is too warm, as shown in Figure 2. For use in skylights, the material is formulated to turn white in response to outdoor sunlight instead of indoor temperature, thereby transmitting a constant level of illumination while outdoor sunlight levels vary hourly and seasonally by a factor of 10 (see Figure 3). Cloud Gel was invented for its largest market: solar heat collectors. With Low-E, it makes possible an entirely new solar architecture that is a no-brainer to design, is free, and works much further north, where it is needed. To learn how the molecules and electrons in these materials work, see Section 18.