Look for "warm edge" spacers which are designed to lower the window U-factor and reduce condensation at the edge of the window. In addition, they provide accommodation for thermal expansion and pressure differences, while also preventing moisture and gas leaks.Ī variety of spacers are available with different impacts on the window U-factor. Spacers with associated sealants are used to keep the layers of glazing the correct distance apart. It has better thermal performance than argon but is also more costly.
Krypton can be used when the space in thinner than usual - usually about ¼ inch. In order to minimize heat transfer between the interior and exterior of the window, the space between glazing layers, usually about 1/2", is filled with argon or krypton gas both are inert, non-toxic, clear, and odorless.Īrgon is most commonly used because it is inexpensive and performs well in the typical 1/2" space. These films are inexpensive compared to total window replacements, last 10 to 15 years without peeling, save energy, reduce fabric fading, and increase comfort. Different types of low-e coatings have been designed to allow for high solar gain, moderate solar gain, or low solar gain, and and they can also be tuned to control the amount of visible daylight transmitted.Īlthough low-e coatings are usually applied during manufacturing, some are available for do-it-yourselfers. The low-e coating lowers the U-factor of the window, and can manage the daylight transmittance as well as the solar heat gain through the glazing system.
Windows manufactured with low-e coatings typically cost about 10% to 15% more than regular windows, but they reduce energy loss by as much as 30% to 50%.Ī low-e coating is a microscopically thin, virtually invisible, metal or metallic oxide layer deposited directly on the surface of one or more of the panes of glass. Low-emissivity (low-e) coatings on glass control heat transfer within the insulated glazing.