WINDOW CONDENSATION The Learning Center Low-E glass reduces heat conducted through the glass from the warm interior of the home to the outside glass surface. Heat conduction can be reduced by as much as 50 percent with an efficient Low-E coated glass. This reflected heat energy reduces the outside glass temperature and can result in condensation on the glass. Exterior condensation is actually an indication that the insulating glass in the window is performing as it should. Low-emissivity glass is designed to reduce heat conduction through the glass unit, thus holding heat in your home on cold days. With this improved performance, the surface temperature of the exterior glass remains cool—and the moist air in contact with that cold outer glass turns into condensation. This is not a fault of the insulating glass—it actually indicates how well the Low-E glass is working. Exterior condensation on windows actually means that the windows are doing their jobs properly. The more energy-efficient your windows are, such as those with Low-E glass, the more likely they are to experience condensation on some portions of the window’s exterior. In fact, under the right combination of humidity, temperature and air flow across the inside and outside surfaces of the window, condensation could form on much of the window’s exterior. On less efficient windows, such as those without Low-E glass, the outside surface temperature is a few degrees warmer because of the energy flow through the glass. This will result in a surface temperature above the dew point. This will decrease the likelihood of condensation on the exterior, but you are consuming more energy in the process.           8. How does low-emissivity (Low-E) glass affect exterior condensation? < back to list of questions about window condensation 1-877-SWING CLEAN info@energyswingwindows.com 3245 Miracle Drive Murrysville, PA 15668 724-387-2991 PA Contractor ID PA001856