Insulating Glass: The Core Material And Technological Innovation of Energy-saving Buildings

1. Definition and classification of insulating glass：

Insulating glass is composed of two or more pieces of glass combined with high-strength sealant and spacer strips, forming a dry gas layer (such as air or inert gas) in the middle. It has functions such as heat insulation, sound insulation, and anti-condensation. It is widely used in building doors and windows, curtain walls, and transportation. According to structural and functional differences, insulating glass can be divided into the following types:

Classification by function: general type, functional composite type (such as fire protection, sound insulation composite), point multifunctional type.

Classification by number of layers: double-layer, triple-layer and multi-layer insulating glass. The more layers, the more significant the heat insulation and sound insulation effect.

Classification by spacer material:

Metal spacer (such as aluminum strip): high thermal conductivity but long sealing life;

Composite rubber strip (such as super spacer): low thermal conductivity and better energy saving effect, but short early sealing life.

2. Performance advantages and key technical factors：

• Energy-saving performance

The heat transfer coefficient (Ug value) of insulating glass is the core indicator to measure its energy-saving effect. The Ug value can be significantly reduced by the following technologies:

Filling with inert gas: Argon has become the mainstream choice due to its low cost and low thermal conductivity (Ug value can be reduced to 1.3), which is better than air (Ug value is about 2.75).

Low-E coating: Low-emissivity coated glass can reduce radiant heat transfer by 60%, and the Ug value can be optimized to below 1.3 when combined with argon.

Optimization of spacing layer thickness: The optimal thickness when argon is filled is 16mm, while air requires 18mm to achieve a similar effect.

• Durability and sealing technology

Dual-channel sealing structure: The use of continuous spacing strips and 3A molecular sieve desiccant can greatly extend the sealing life (up to 100 years in some cases).

Super spacing strips: With both low thermal conductivity and high sealing, it solves the condensation problem of traditional aluminum spacing strips and becomes the new generation of technology direction.

3. Comparison between insulating glass and other glass：

Compared with laminated glass, hollow glass has more advantages in the following scenarios:

Heat insulation and sound insulation: The air layer of hollow glass can reduce noise by 30-44dB, while laminated glass focuses more on explosion-proof safety.

Energy-saving demand: The Ug value of hollow glass is significantly lower than that of laminated glass, which is suitable for buildings with high insulation requirements.

Application scenario: Laminated glass is used for the top of the sun room to prevent explosion, and hollow glass is used for the facade to achieve warmth in winter and coolness in summer.

4. Technological innovation and future trends：

• Multi-screen insulating glass

Adding multiple screen layers to traditional insulating glass, it has both UV protection and condensation removal functions, and the K value can be as low as 0.54W/㎡·K, which far exceeds the insulation effect of traditional 370mm brick walls and is suitable for passive low-energy buildings.

• Intelligent and multi-functional composite

Combined with intelligent dimming glass, self-cleaning coating and other technologies, the functionality of the building facade is improved1.

Double silver Low-E coating, warm edge technology, etc. further reduce the Ug value and promote the development of ultra-low energy buildings

5. Key details in the manufacturing process：

• Molecular sieve selection: 3A molecular sieve should be used because it only absorbs water molecules without affecting the pressure stability of the hollow layer gas (such as nitrogen and oxygen).

• Sealant quality: Inferior sealant is prone to fogging or leakage, affecting the service life, and high airtightness composite sealant is required.

As the core material for energy saving in modern buildings, the technology of insulating glass is moving towards high performance, long life and multi-function. By optimizing gas filling, spacer design and coating technology, its energy saving efficiency has approached or even exceeded that of traditional wall materials. In the future, with the popularization of new technologies such as multi-screen insulating glass, insulating glass will play a more critical role in green buildings and passive houses.