Low-e coated glass allows building designers to strike a desired balance between visible light transmittance and solar efficiency.
With low-e coated glass, building designers can strike a desired balance between visible light transmittance and solar efficiency. ITI Glass stocks several low-e products and carries the full line of Solarban solar control low-e glazings.
Low-emissivity (low-e) glass selectively transmits visible light and filters short- and long-wave radiation from the sun — the main causes of heat gain and sun damage in buildings. Low-e glass increases a window’s efficiency two ways: First, by reducing the amount infrared radiation that transmits through a glazing, low-e glass decreases heat gain. Second, low-e minimizes heat loss and the effects of the outdoor climate on a building’s controlled interior temperature by reflecting heat back to its source. In this capacity, low-e acts as a transparent barrier between indoor and outdoor climates, reducing heat transfer through a window.
MSVD and Pyrolytic Low-e
There are two types of low-e coatings, hard coat, or pyrolytic; and soft coat, or MSVD (magnetron sputter vacuum deposition). Appropriate specification of architectural glass should maximize energy efficiency. This can lower energy use of regulated heating and cooling systems and reduce the need for electric lighting.
Hard coat low-e glass performs most efficiently in climates where interior heating is most important by allowing higher levels of infrared radiation to transmit. This results in more effective use of natural heating from the sun. However, if lower U-values are desired for more efficient thermal insulating, a soft coat low-e should be specified.
Soft coat low-e glass is distinguished by higher light to solar gain (LSG) ratios and lower U-values. These perform best in climates where interior cooling and thermal insulation are most important. By effectively reducing infrared transmittance, soft coats reduce the overall heat gain through a window. This can decrease energy use of regulated cooling systems. Soft coats also reflect interior heat back to its source, resulting in less radiant heat transfer and more effective insulating performance.
Standards
ITI Glass fabricates all low-e coated glass in accordance with ASTM C1376-03 Standard Specification.