Low-emissivity glass, the full name of low-emissivity coated glass, also known as Low-E glass (abbreviation of Low Emissivity Coated Glass), is named because of the extremely low surface emissivity of the coated layer. The "low emissivity" of low emissivity glass means that under the same temperature conditions, the film surface radiates lower heat than the ordinary glass surface.

Low-E glass has a high transmittance for visible light with a wavelength range of 380-780nm, which is conducive to indoor lighting; it has a high reflectance for solar near-infrared radiation with a wavelength of 780-2500nm; it also has a high reflectance for mid- and far-infrared radiation. And it has the characteristics of low emissivity, that is, the radiant heat of the glass on the surface of the low emissivity film is very low. (What does the "radiation" of low-e glass mean?)

In layman's terms, low-emissivity glass can not only reflect most of the infrared radiation from the sun, but also reduce the transfer of indoor and outdoor thermal radiation energy under the premise of ensuring a high visible light transmittance, and has excellent heat insulation and heat preservation performance.

We know that the emissivity of the film surface is an important parameter for evaluating the performance of low-emissivity glass. GB/T 18915.2-2013 "Coated Glass Part 2: Low-E coated glass" stipulates that the emissivity of offline low-E coated glass should be less than 0.15, and the emissivity of online low-E coated glass should be less than 0.25.

-转自中国玻璃网