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September 27, 2011 -
Windows & Exterior Walls
Today's tip is about some strategies for shading windows and roofing from the sun. If done correctly, shading provided by landscaping or other exterior shading elements can result in significant energy savings.
Use exteriors overhangs and solar shading devices to control heat gain into buildings.
It's important to properly size overhangs, especially for south-facing windows, so that when the sun is directly overhead during summer, the shading devices should shade windows completely to minimize heat gain. In the winter, when the sun is at a lower angle, the solar shading devices or overhangs should allow the sun to enter, to help warm the interior. It's a careful balancing act; one best mapped out with modeling software, if possible.
Other forms of solar shading devices include cover panels over skylights, insulated shutters, awnings and landscaping. There are even new solar shading products with photovoltaic cells on top, so they not only shade windows, but also produce energy.
Another strategy is to use creative landscaping to act as natural solar shading.
According to the Department of Energy, shading and evapotranspiration (the process by which a plant actively moves and releases water vapor) from trees can reduce surrounding air temperatures as much as 9° F (5°C).
Deciduous trees with high, spreading crowns can be used to be block heat in the summer but let it in during the winter. If you hope to block heat year-round, use dense evergreen trees or shrubs.
Additionally, use ground cover plants around the facility - instead of dark asphalt surfaces - can lower the ambient temperature, requiring less energy for cooling in the summer.