LOW-E insulating glass, what kind of glass is it?

1What is LOW-E glass?

LOW-E glass is low-emissivity glass. It is formed by coating the glass surface to reduce the emissivity E of the glass from 0.84 to below 0.15.

2What are the characteristics of LOW-E glass?

It has high infrared reflectivity and can directly reflect far-infrared heat radiation.

The surface emissivity E is low, and its ability to absorb external energy is small, so it re-radiates less heat energy.

The shading coefficient Sc has a wide range, and the solar energy transmission can be controlled as needed to adapt to the needs of different regions.

3Why does LOW-E coating reflect heat?

The LOW-E film is coated with a silver layer, which can reflect more than 98% of far-infrared heat radiation, thus directly reflecting heat like a mirror reflecting light. The shading coefficient Sc of LOW-E can be from 0.2 to 0.7, so that the direct solar radiation entering the room can be controlled as needed.

4What are the main types of mature coating glass processes?

There are two main types: online coating and vacuum magnetron sputtering coating (also called offline coating).

Online coated glass is manufactured on a float glass production line. This kind of glass has a single variety, poor heat reflectivity, and low manufacturing cost. Its only advantage is that it can be hot-bent.

Off-line coated glass has rich varieties, excellent heat reflection properties and obvious energy-saving properties. The disadvantage is that it cannot be hot-bent.

5Can LOW-E glass be used as a single piece?

LOW-E glass manufactured by the vacuum magnetron sputtering process cannot be used as a single piece and can only be synthesized into insulating glass or laminated glass. But its emissivity E is far lower than 0.15 and can be as low as 0.01.

LOW-E glass manufactured by the online coating process can be used as a single piece, but its emissivity E=0.28, strictly speaking, it can no longer be called LOW-E glass (scientifically, objects with emissivity E0.15 are called low-emissivity object).

6How does LOW-E glass work in summer and winter?

In winter, the indoor temperature is higher than the outdoor temperature, and far-infrared heat radiation mainly comes from indoors. LOW-E glass can reflect it back into the room to prevent indoor heat from leaking out. For part of the solar radiation from the outdoors, LOW-E glass can still allow it to enter the room. This part of the energy is absorbed by indoor objects and then converted into far-infrared heat radiation and remains indoors.

In summer, when the outdoor temperature is higher than indoors, far-infrared heat radiation mainly comes from the outdoors. Low-e glass can reflect it out and prevent heat from entering the room. For solar radiation from outdoors, you can choose LOW-E glass with a low shading coefficient to limit its entry into the room, thereby reducing certain costs (air conditioning costs).

7What is the role of filling argon gas in LOW-E insulating glass?

Argon is an inert gas with poorer heat transfer than air, so filling it into insulating glass can reduce the U-value of insulating glass and increase the thermal insulation of insulating glass. For LOW-E insulating glass, argon gas also has the function of protecting the LOW-E film layer.

8How much UV rays can LOW-E glass attenuate?

Compared with ordinary single piece transparent glass, LOW-E glass can reduce UV rays by 25%. Compared with heat-reflective coated glass, LOW-E glass reduces UV rays by 14%.

9Which surface of the insulating glass is most suitable for the LOW-E film layer to be located on?

The insulating glass has 4 surfaces, and they are 1#, 2#, 3#, and 4# from the outside to the inside. In areas where the heating demand exceeds the cooling demand, the LOW-E film layer should be on the 3rd surface. On the contrary, in areas where the cooling demand exceeds the heating demand, the LOW-E film layer should be located on the 2nd surface.

10How long does the LOW-E coating last?

The duration of the coating layer is the same as the duration of the sealing of the insulating glass space layer.

11How to determine whether insulating glass is coated with LOW-E film?

Monitor and identify according to the following steps:

A. Observe the four images presented in the glass (in other words, there are 4 flames or 4 objects).

B. Place a match or bright object in front of the window (whether you are indoors or outdoors). If it is LOW-E glass, the color of one image is different from the other three images. If the colors of the four images are the same, it can be determined that LOW-E glass is not installed.

12Is there anything users need to do to maintain LOW-E glass products?

unnecessary! Because the LOW-E film layer is sealed between the insulating glass or laminated glass, it requires no maintenance and only needs to keep the glass surface clean.