Low-E glass, short for low-emissivity glass, is a type of glass that has a microscopically thin, transparent coating that reflects long-wave infrared energy (or heat) . The coating is much thinner than a human hair and is applied to the glass to minimize the amount of infrared and ultraviolet light that comes through the glass, without minimizing the amount of light that enters your home. Low-E coatings keep the temperature in your home consistent by reflecting the interior temperatures back inside, which results in better control of energy. Low-E glass works by reflecting heat back inside during the winter months and bouncing it off during the summer months.
Low-E glass can be made with different types of coatings, and the effectiveness of glass with Low-E coatings is measured by several factors, including U-value, solar heat gain coefficient (SHGC), and visible transmittance (VT) . The iron content of glass can also be controlled to change the thermal emissivity properties of glass, but this is not used for windows.
Low-E glass is more energy-efficient than regular glass windows, and it can save you money on energy costs and reduce fading to furniture. Although Low-E glass can be a slightly bigger investment than regular glass windows, the initial cost of the additional coating is typically just a couple more dollars than regular glass windows, and the extra money you spend generally pays for itself in energy savings over the lifetime of your window.
