This story was originally published at Green Building Elements. Reprinted with permission.
Big things are happening in the world of energy efficient windows. Where once window manufacturers simply added another layer of glass and called it a day, new research and materials make it possible to create windows that can cut annual energy bills by up to 20%. Apply that number to all the buildings in the world and you have removed millions of tons of carbon dioxide from the air, not burned millions of barrels of oil for heat and electricity and saved families and business billions of dollars. No wonder the market for energy efficient windows is expected to grow by 19% a year to more than $ 5 billion dollar by 2020 according to Industry ARC, a global research firm.
Windows are wonderful. They let sunlight in and see the world outside. But they are weakest link when it comes to insulating our homes and commercial buildings. On average, a window has less than 10% of the insulating power of the walls that surrounds it. Not only does it let precious heat out in the winter, making our furnaces work harder, it also lets unwanted heat in during the summer, putting an extra load on air conditioning equipment.
Smart windows change the equation. They have glass panes that are coated with a thin layer of metal oxide. You can’t see it, but it’s there. What’s so great about this coating? A small electrical voltage applied to it lets it darken the window, which reduces the amount of heat transference through the glass. It also controls the amount of light entering a room without the use of blinds, draperies or shades.
Often called electronic switchable glass, it is the focus of attention at such global glass companies as Saint-Gobain, DuPont, Asahi Glass, Hitachi Chemical, Corning Inc., Guardian Industries, PPG Industries Inc., Smartglass International, Gentex Corporation, Vision Systems and others. Coating companies such as Wenzhou Yongfeng, Corning, DuPont, Richtech, and Sekisui are involved in the research and development of advanced coating technology..
Listen to what Rao Mulphuri, CEO of View, a start-up window company in California has to say. “Every View window has an IP address and controllable through the Internet. Everything is at your fingertips and then it can tie a number of other things together. The windows can now talk to the lighting and HVAC system, and on a more global level it could connect to the future smart city and smart grid,” he told Forbes.
That means, every window in an entire building may soon be able to be individually controlled every hour of the day. For instance, the glass on one side might be left clear to let in morning sun, while the glass on the other side is made darker to avoid heat gain from the afternoon sun. Individual windows could also be controlled to compensate for shading from a nearby tree, or even from a passing cloud!
Mulphuri also claims the windows will be energy efficient, promising that businesses and homes that will adopt the technology will be able to save 20 per cent of their electricity bill in just one year. View has just received $75 million in funding from the New Zealand national pension fund.
Switchable glass has many interior uses as well. It can be used to make clear walls that can be darkened for privacy when needed. The degree of darkening depends solely on the amount of voltage applied to the coating. The technology can also be used in automobiles to help bring light into the interior but control solar heat gain in warm climates.
The possibilities are endless. Soon, the old expression, “It’s as clear as glass,” may no longer apply.