How Smart Windows Work

Dynamic glazing—coated plastic or glass that changes tint in response to light, heat, or electricity—has been around for decades as a feature of eyeglasses, mood rings, and digital watches. Similar technologies have been developed more recently to make dynamic glass at a much larger scale for architectural applications. These so-called smart windows can help conserve energy by sometimes blocking unwanted heat gain to reduce the need for cooling and at other times letting in natural daylight and passive solar heat to reduce the need for artificial lighting and space heating.

Smart windows are intended to take the place of louver systems and other shading devices; unlike most shades, however, smart windows let some daylight in and allow views to the outdoors even when fully deployed, and they avoid visual clutter and surfaces that collect dust. Although there are several types of dynamic glazing, the two primary technologies currently in use are electrochromic (responsive to current) and thermochromic (responsive to heat).