Low-E Glass

What is low-E glass?
How many types of low-E glass are on the market?
Is all low-E glass the same?

Low-E glass refers to glass with a low-emissivity coating. It reduces heat gain or loss by reflecting long-wave infrared energy (heat) and therefore, decreases the U-value and solar heat gain, and in doing so, improves the energy efficiency of the glazing. Because of its relative neutrality in appearance and energy efficiency, low-E glass is widely used in residential and commercial buildings and is expected to continue to increase in usage in the coming years.

Based on how it is manufactured, low-E glass can fall into two categories: pyrolytic deposition (hard coat) and vacuum deposition (sputter coating) low-E. The difference between the two is that the pyrolytic deposition method applies various metals to molten glass during the float glass manufacturing process. Vacuum deposition, on the other hand, applies various metals off-line in a large vacuum chamber. Pyrolytic coatings have higher solar heat gains and U-values and may not meet energy codes. They also can be less crisp in appearance compared to sputter coatings. Sputter coatings are offered in a wide variety of color and performance options, including post-temperable versions, and can meet and exceed energy code requirements.

Guardian Industries manufactures SunGuard brand post-temperable sputter coatings at multiple locations in the U.S., Europe and South America. The SunGuard coatings are sputter coatings, not pyrolytic.