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Residential Structural Certifications
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back to Windows and Doors - in Depth
Glazing
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Often the most attractive feature of a
house, windows can also be the least energy efficient. Glass is not a great insulator, which means that windows are a major source of heat escaping or entering a home. How your windows are glazed can make a big difference in this dynamic. Windows are rated according to how much heat can escape through the glass (measured by R-value) and through an entire window per hour (measured by U-value). Windows with a high R-value allow less heat to escape; a low U-value means a window conserves more energy. |
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These days, many windows are
double-glazed—they have two panes of glass separated by a thin space. Some
are even triple-glazed. The space between glass panes may be filled with
air or an inert gas such as Argon. This, as well as thin low-emissivity
(low-E) coatings, help reduce heat transfer. Homeowners in hot, sunny climates frequently choose windows with ultraviolet (UV) coatings that keep the sun's rays from fading curtains, furniture, and carpets. Some UV coatings come tinted, which also helps to keep the house cool. Also available are special polymer coatings that can repel dirt, reducing the need for window washing. |
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