BuildingGreen, Inc., a publisher of green building news, has selected windows that can be electronically switched from clear to tinted, as one of the top ten energy efficiency products of 2006. Called SageGlass®, the product from Sage Electrochromics, Inc. uses "electrochromic" (EC) tungsten oxide coatings that turn dark when a voltage is applied to them, allowing automated or manual control of daylighting.
SageGlass® is an electronically tintable exterior glazing that provides glare control on demand while preserving views. Unlike earlier switchable glazing products that degraded with exposure to UV light, SageGlass is a multi-layer, thin-film tungsten-oxide coating that is as durable as low-emissivity coatings. The glazing uses 0.28 W/ft2 to switch the glass from clear to tinted state, a process that takes several minutes, and 0.1 W/ft2 to maintain that tinted state. Used with typical clear glass in an insulated glazing unit, SageGlass reduces the visible transmittance from 62% to 3.5% while reducing the solar heat gain coefficient from 0.48 to 0.09.