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Windows Windows are thermal holes. An average home may lose 30% of its heat or air-conditioning energy through its windows. Energy-efficient windows save money each and every month. There are even some cases where new windows can be net energy gainers. The payback period for selecting energy-efficient units ranges from two years to ten years. In new construction, their higher initial cost can be offset because you'll probably need a smaller, less expensive heating and cooling system. And more-durable windows may cost less in the long haul because of lowered maintenance and replacement costs. Plus, you'll be more comfortable the whole while you live with them. Windows lose and gain heat by conduction, convection, radiation and air leakage. This heat transfer is expressed with U-values, or U-factors. U-values are the mathematical inverse of R-values. So an R-value of 2 equals a U-value of 1/2, or 0.5. Unlike R-values, lower U-value indicates higher insulating value. Let the Sunlight InIn a cold climate we welcome the sun's heat and light most of the time. And once we capture the heat, we don't want to give it up. In a warm climate, we don't want the heat, but we do want the light. Advances in window technology let us have it both ways. More on Window Technology. Enjoying the ViewEven though tinted windows can help keep heat out in hot climates, windows with a high visible transmittance (VT) can help save energy by adding daylighting. More on VT. Taking the HeatWindows are an efficient way to allow both heat and light into your home. There are many different glass coatings and window tints to combine and create the perfect window for your home or building according to location and climate. More on Glass Coatings. |