Pleotint launches smart windows

Pleotint L.L.C., Grand Rapids, Mich.,has just launched the nation's first commercially available window film for laminated glass that darkens as it's warmed by the sun to significantly cut the energy costs of operating office buildings, commercial buildings, schools and homes. Use of these self-tinting windows reduces glare and increases occupant comfort while also reducing or eliminating the need for blinds and drapes.

The West Olive, Mich.-based company used its patented technology to construct what it believes to be the world's largest chromogenic windows that change tint automatically to reduce unwanted solar heat gain and glare from entering a building – while always preserving the view to the outside. Pleotint supplied rolls of film that were laminated and fabricated into windows with a sizes of up to 5-foot by 10-foot.

The company will be demonstrating its technology from Nov. 16-18 at the Greenbuild 2010 exhibition, booth 1976, McCormick Place West in Chicago. The thermochromic technology allows changes in light transmission due to heat provided by absorbed sunlight. Pleotint describes the variable light transmission as adaptive glazing as the windows respond to the amount of direct sunlight on the window any time of day and any day of the year.

In a recent commercial application installed in early August, thermochromic film made by Pleotint and fabricated into windows has significantly reduced the temperature of a southwest-facing office at Calvin College in Grand Rapids, Michigan that was having a problem with unbearable temperatures due to the heat load from exposure to direct sunlight. Office windows comprising the thermochromic film sandwiched between two panes of glass darken as they are warmed by the sun, controlling the temperature and glare in the office by decreasing total sunlight transmission by as much as 85 percent when needed.

"We were having some real issues with heat in the space -- sometimes the temperature would rise to as high as 90 degrees," says Philip Beezhold, director of physical plant at the college. "It used to be that if you touched the printer in that office on a sunny day, it would be uncomfortably hot."

Beezhold says drapes and blinds in the office helped to control glare coming from afternoon sunlight, but they are of very limited use in minimizing heat because they absorb the sunlight and release the heat inside the room. "We are very pleased with Pleotint windows," he says. "They worked very well during the summer, and we'll see how they react in the winter. We are expecting them to be quite effective because they have a higher insulating value than our old windows."Having invested more than a decade in research and development, Pleotint now has begun manufacturing and marketing the lamination film nationwide to architects, construction companies and homebuilders, says Pleotint founder and inventor Dr. Harlan Byker.

Byker, who is credited with developing the chemistry of the electrochromic dimming rearview mirrors manufactured by Gentex Corporation that can be found on more than 100 million vehicles worldwide, launched Pleotint to solve the problem of dimming windows in buildings as a way to control energy costs and improve ergonomics for office workers.Byker has a doctorate in physical chemistry and currently is the holder of 48 US Patents. He became intrigued by the possibility of using thermochromic film to deal with the heat load from windows after leaving Gentex in late 1997. Byker says his desire to create a window that was sunlight responsive, self-tinting with high insulation properties was especially daunting since there weren't any appropriate thermochromic materials commercially available in the late 1990s.

Today, the result of his group’s research is the patented thermochromic technology that is fundamentally different and simpler than other smart window technologies that rely on electric charges or directly use photons of light to reduce light transmission. Thermochromic windows are installed the same way as traditional windows, and thermochromic technology works without the need for sophisticated controls, wires, power supplies or manual operations to reduce heat loads in buildings.

"The only time you want to tint windows is when there is sunlight is directly on it," Byker says. He says the Pleotint window allows approximately 50 percent transmission of visible light on cloudy days or at night and it continuously changes its visible transmission down to 10 percent or less, depending on the sunlight angle and intensity. Tinted glass can be combined with the film to provide the architect/building owner the aesthetic look, from the outside, that they desire.

James Vanderveen, a principal with GMB Architecture + Engineering in Holland that serves the building industry, says his firm completed a study of the Pleotint system in 2006 that showed overall energy cost savings of from 17 percent and up to 30 percent with the use of the Pleotint's window system versus industry standard windows.

Exact cost comparisons between ordinary windows and Pleotint film-equipped windows are tricky because ordinary window prices vary widely depending on their features, such as two- or three-pane configurations, but Pleotint estimates payback on its windows is about five to seven years. Pleotint technology can be used in two- or three-pane windows, as well as large custom windows such as the 5-foot by 10-foot windows that a contractor recently purchased.

Pleotint's technology maximizes the amount of daylight while minimizing direct solar heat gain, but it also controls glare that can be distracting for people, says Fred Millett, the company's director of sales and marketing. "People generally want a fixed amount of illumination in the workplace," he says. "At certain times of the day and certain times of the year, they may get way too much daylight. Our film controls that glare."