Electrochromic ‘smart’ windows consist of two glass panes with several layers sandwiched in between. It works by passing low-voltage electrical charges across a microscopically-thin coating on the glass surface, activating an electrochromic layer which changes color from clear to dark. The electric current can be activated manually or by sensors which react to light intensity. One advantage of the electrochromic window is that it only requires electricity to change its opacity, but not to maintain a particular shade. Unlike blinds, electrochromatic windows are capable of partially blocking light while maintaining a clear view of what lies behind the window.

SPD (suspended-particle-device) ‘smart’ windows are constructed by using two panes of glass separated by a conductive film with suspended, light absorbing, microscopic particles. Microscopic light-absorbing particles are dispersed within a thin film. When no electrical voltage is applied to the film, these particles absorb light, making the glass dark. When voltage is applied, the particles align and allow light to pass through. By simply adjusting the electrical voltage manually or automatically, the amount of light passing through the SPD-glass product can be controlled quickly and precisely. While this type of smart window is capable of changing at the turn of a button, one disadvantage is that electricity is required to keep the window transparent.

For this project I have assumed ‘SPD type’ electrochromatic glass. The window illustrated above uses a double pane configuration however the 'Moss' design is laminated. No information was available regarding its specification.