‘Smart Glass’ Technology Reduces Solar Heat Gain in Buildings

Windows are often the most inefficient part of a building envelope and are responsible for heat loss in cold months and solar heat gain in warm months. Sunlight entering a home can increase cooling loads by up to 20%. In some instances, glare from the sun can make it difficult to see a computer or other LCD screen, requiring the blinds to be pulled, negating the benefits of natural light. Sunlight can also fade furniture, carpets, and drapes, increasing building owners' maintenance costs.

SAGE Electrochromics, Inc., with assistance from DOE's Inventions and Innovation Program, developed SageGlass® product technology to create windows and skylights that switch from clear to dark with the push of a button. Within 5-10 minutes, the electrochromic (EC) glass completely changes, depending on the size and temperature of the pane. The variable tint feature of the glass prevents glare, fading, and heat gain without the loss of a view. Without the drawbacks of traditional glass, this technology allows architects the freedom to design with daylighting, creating well-lit, comfortable buildings.

This EC glass modulates light transmission and solar heat gain by sending an electrical charge through the glass. The glass is made up of five separate layers of ceramic materials; when voltage is introduced, the glass lightens or darkens as needed. The electricity used to operate 1,500 square feet of SageGlass window is less than a 60-watt light bulb. The glass can be altered manually via a wall switch or as part of an integrated building management system so that windows can be programmed to tint depending on input from timers, motion sensors, or similar controls.

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<h4>Overview</h4><ul><li>Developed by <a href="http://sageglass.com/">SAGE Electrochromics, Inc</a>., a wholly owned subsidiary of Saint-Gobain.</li><li>Commercialized in 2003.</li></ul><h4>Applications</h4><p>Can be used in any building with windows or skylights, including homes and large public buildings; is particularly appropriate for hospitals, schools, libraries, data centers, clean rooms, etc.</p><p>&nbsp;</p><h4>Capabilities</h4><ul><li>Provides 62% &ndash; 2% light transmission variability in multiple independent zones within each window.</li><li>Offers variable solar heat gain of 0.47 &ndash; 0.09.</li><li>Prevents sunlight from damaging artwork, furniture, and carpet.</li><li>Reduces glare so windows do not have to be shaded or blocked.</li><li>Reduces building energy consumption by up to 20%.</li><li>Reduces building HVAC costs by up to 30% and lighting costs by 60%.</li></ul><h4>Benefits</h4><h5>Adaptability</h5><p>Can be configured to operate by a wall switch or as part of a building&rsquo;s automation system and is appropriate for both residential and commercial applications.</p><p>&nbsp;</p><h5>Energy Savings</h5><p>Reduces annual cooling loads in commercial buildings by 20% and peak electricity demand in most of the United States by 19% to 26%.</p><p>&nbsp;</p><h4>Contact Information</h4><p><strong>Neil Sbar</strong><br />(507) 331-4902<br /><a href="mailto:neil.sbar@sageglass.com">neil.sbar@sageglass.com</a><br /><a href="http://sageglass.com/">SAGE Electrochromics, Inc</a>.</p>