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An average of 40 percent of residential winter heating energy is lost through windows. Small commercial buildings have a similar problem. Window treatments have long been used to provide functional and aesthetic additions to existing windows. Exterior shutters, for instance, protect expensive glazing from extreme winds, branches and other storm hazards, and provide an attractive exterior feature. Similarly, drapes provide privacy, can reduce light infiltration, and help reduce winter heat loss, when drawn closed.

BPA is looking at the insulation value of cellular window shades, which incorporate a honeycombed cross section with air-trapping pockets, and automated controls for interior window shades that respond to available sunlight and need for controlling solar heat gain and glare.

Current Stage: Emerging Technology Assessment

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