Low-E coated windows offer long-lasting performance
Our front windows face southwest. We have no shade trees in the front yard, so we are expecting the front rooms to get hot this summer. We also have condensation between the panes. We plan to replace the glass, but I am getting conflicting advice. Should I get low-E glass and rely on it to block the IR heat waves, or get clear glass and have an IR-reflective film applied? Which will give me the best results? — Angie's List member Roger Linville
Miguel Wellington, general manager for highly rated Sierra Window Concepts in San Diego, says IR reflective films will help, but won't have the efficiency of the newest triple layer low-E coatings that are sprayed onto the glass at the factory and then cooled to create a bond.
"Condensation between the panes of glass is an indicator that the sealing system of the glass unit has broken down, also reducing the efficiency of the double-pane system," Wellington says. He also says infrared reflective film is a budget-minded quick fix and won't have the long lasting performance of replacing the dual-pane glass units with low-E3 technology.
Dan Dean, owner of highly rated Window Factory in San Diego, says an insulated glass unit with a high performance low-E coating is the best option to prevent heat gain through a window.
He says applying aftermarket films to single-pane glass works to block infrared and ultraviolet light, but it's not a good idea with dual-pane glass because the film is applied to the inside of the window. Because of this, Dean says, heat energy passing through the dual-pane glass is reflected back inside the insulated glass and can cause excessive heat buildup inside the unit, resulting in condensation.
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