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By John A. D’Annunzio
May 2015 -
Windows & Exterior Walls Article Use Policy
The biggest deterrent to energy efficiency at the building envelope (roofs, walls, and windows) is heat loss at exterior components. Implementing various methods to decrease (or eliminate) heat loss at these components is the best way to contribute to overall building performance. Following are some specific considerations for energy efficiency, beginning with weather—proofed windows.
Windows have long been a source of excessive heat loss due to non—energy—efficient materials and components. Now, material technology has advanced to the point where not only are energy—efficient replacement windows available, but methods exist to increase the energy efficiency of existing windows. There are three main methods with existing windows: adding storm windows, weather stripping, or using weather coverings. Adding storm windows reduces air leakage and improves comfort. Applying weather stripping at joint openings eliminates heat loss. Window treatments, such as film, can reduce heat loss in the winter and heat gain in the summer.
If the existing windows are old and inefficient, it may make economic sense to replace them. New energy—efficient windows will help pay for themselves through lower heating and cooling costs and — in some cases — reduced lighting costs. Energy—efficient methods and materials now available include these:
A prevalent source of increased heat loss is from building joints at windows and exterior walls. Facility managers can use infrared thermography to see the significant amount of heat loss that is generated at these locations. Openings are created when the sealant at the building joint deteriorates. Most building sealants have limited lifespans, and facility executives should view them as they do other maintenance components throughout the building, inspecting them regularly and restoring or replacing them as needed.
Exterior strategies can also affect interior energy. Here are two ways that’s true.
Weather-Proofed Windows and Energy Efficiency
Target Heat Loss at Walls, Roofs to Boost Building Performance
Materials on Roof Surface Can Build Energy Efficiency