What is Low-E Glass?

Float Glass is one of the most popular and versatile building materials used today, due in part to its constantly improving solar and thermal performance. One way this performance is achieved is through the use of passive and solar control Low-E glass coatings. So, what is low-E glass? In this section, we provide you with an in-depth overview of coatings.

Low-e glass(low emissivity glass), also known as low-radiation glass, is coated on the float glass surface of multi-layer metal or other compound composition of the film products. Has high to visible light through the coating layer and the high cosco infrared reflection characteristics, make its compared with ordinary sheet glass and traditional building reflective glass, excellent heat insulation effect and good transmittance.

Low-e glass Coating Types & Manufacturing Processes

There are actually two different types of low-e glass coatings: passive low-e glass coatings and solar control low-e glass coatings. Passive low-e glass coatings are designed to maximize solar heat gain into a home or building to create the effect of “passive” heating and reducing reliance on artificial heating. Solar control low-e glass coatings are designed to limit the amount of solar heat that passes into a home or building for the purpose of keeping buildings cooler and reducing energy consumption related to air conditioning.

Both types of low-e glass, passive and solar control, are produced by two primary production methods – pyrolytic, or “hard coat”, and Magnetron Sputter Vacuum Deposition (MSVD), or “soft coat”. In the pyrolytic process, which became common in the early 1970’s, the coating is applied to the sheet glass ribbon while it is being produced on the float glass line. The coating then “fuses” to the hot sheet glass surface, creating a strong bond that is very durable for flat glass processing during fabrication. Finally, the flat glass is cut into stock sheets glass of various sizes for shipment to fabricators. In the MSVD process, introduced in the 1980’s and continually refined in recent decades, the coating is applied off-line to pre-cut flat glass in a vacuum chambers at room temperature.

Because of the historic evolution of these coating technologies, passive low-e glass coatings are sometimes associated with the pyrolytic process and solar control low-e glass coatings with MSVD, however, this is no longer entirely accurate. In addition, performance varies widely from product to product and manufacturer to manufacturer,but performance data tables are readily available and several online tools can be used to compare all low-e glass coatings on the market.