Why is the anti frost performance of insulating glass good

Source：www.cnxingfu.net Release date： 2025-10-09

Information summary：The excellent anti frosting performance of insulated glass is mainly due to its structural design of "double-layer/multi-layer glass+middle sealed air layer". From the two key dimensions of "blocking heat transfer" and "controlling glass surface temperature", it solves the frosting problem caused by "large temperature difference and rapid heat loss" of ordinary single-layer glass. The specific pri

The excellent anti frosting performance of insulated glass is mainly due to its structural design of "double-layer/multi-layer glass+middle sealed air layer". From the two key dimensions of "blocking heat transfer" and "controlling glass surface temperature", it solves the frosting problem caused by "large temperature difference and rapid heat loss" of ordinary single-layer glass. The specific principle can be decomposed into the following three points:
1、 Intermediate sealed air layer: blocks "heat conduction" and "heat convection", reducing heat loss
The essence of frosting is that the surface temperature of the glass is lower than the dew point temperature of the ambient air (the temperature at which water vapor condenses into liquid water in the air), and further below 0 ℃, the liquid water freezes into frost. Ordinary single-layer glass has fast heat conduction, and in winter, indoor heat will be quickly transferred to the outside through the glass, causing a sudden drop in surface temperature inside the glass (often below 0 ℃), leading to frost formation; The middle sealed air layer of insulating glass can fundamentally reduce heat loss and avoid low surface temperature inside the glass:
1. The low thermal conductivity of air blocks heat conduction
The thermal conductivity of air is only 0.026W/(m · K), much lower than the 1.05W/(m · K) of glass (about 1/40 of glass). The middle air layer is equivalent to establishing a "thermal barrier" between two layers of glass. In winter, indoor heat is difficult to transfer through the air layer to the outside through "thermal conduction" (heat is directly transferred from high-temperature objects to low-temperature objects), thereby slowing down the temperature drop rate of the glass surface and making it difficult for its temperature to drop below 0 ℃.
2. The sealing structure prevents heat convection and avoids heat diffusion
The four sides of the insulated glass are sealed with a double seal of "butyl rubber+polysulfide rubber/silicone rubber" (butyl rubber is responsible for water vapor barrier, and outer rubber is responsible for structural sealing), which can completely block the circulation of the middle air layer and the outside air, forming a "static air layer". This static state can avoid the occurrence of "thermal convection" (the circulation of hot air rising and cold air sinking due to temperature differences) in the air - if the air layer is not sealed, outdoor cold air will enter the layer and convection with indoor hot air, accelerating heat loss; After sealing, the static air layer has almost zero heat convection, further reducing heat loss.
2、 Optional filling of inert gas: further enhance insulation performance and stabilize glass surface temperature
A better insulating glass will be filled with inert gases such as argon and krypton in the middle air layer (with an inert gas ratio of ≥ 90%), and its anti frosting performance is better than that of ordinary air layers. The core reason is that the inert gas has stronger insulation and weaker fluidity
The thermal conductivity of argon is only 0.017W/(m · K), which is about 35% lower than that of air and can more efficiently block heat conduction;
The density of inert gases is higher than that of air (argon has a density 1.38 times that of air), and their flowability is poorer, which can further prevent thermal convection and make it more difficult for the heat in the intermediate layer to diffuse.
Data shows that hollow glass filled with argon gas has a surface temperature 2-3 ℃ higher than ordinary air layer hollow glass in winter, making it more difficult to achieve the "below 0 ℃" condition required for frosting, especially in cold northern regions (outdoor temperature below -10 ℃), where the difference in frost prevention effect is more significant.
3、 Glass surface coating (Low-E film): Reflects infrared heat and locks in indoor temperature
Part of the insulated glass (especially energy-saving types) will be coated with a "Low-E film" on the inner surface of one layer of glass (facing the middle air layer), which can further reduce indoor heat loss by "reflecting infrared heat" and ensure the temperature of the glass inner surface from the source:
Principle: Low-E film is a metal composite film (such as silver, copper, nickel alloy film) that has high transmittance (transmittance ≥ 70%) for "visible light" (used for lighting) in sunlight, but high reflectivity (reflectance ≥ 80%) for "infrared heat" emitted by indoor objects (heat generated by winter heating, human body heat dissipation, etc.);
Function: In winter, the infrared heat inside the room will be reflected back into the room by the Low-E film instead of being transmitted to the outside through the glass, which is equivalent to "locking" the indoor heat, making the surface temperature of the glass closer to the indoor temperature (usually maintained at 5-10 ℃), far higher than the required 0 ℃ for frosting, fundamentally avoiding frosting.
Compared to ordinary uncoated insulating glass: Low-E coated insulating glass can increase the inner surface temperature of the glass by 3-5 ℃ in winter, and even if the outdoor temperature drops to -15 ℃, the inner surface is not easily frosted.

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