The doors and windows, which are one of the four major enclosure components that affect building energy consumption, are generally thin-walled lightweight components, and are weak links in building insulation, heat insulation, and sound insulation. In particular, the thermal insulation performance is the worst. It causes energy loss in buildings through radiation transmission, convection transmission, conduction transmission and air infiltration. The energy loss of common single-layer windows accounts for about 50% of the building's winter insulation and summer cooling energy consumption. %the above. Therefore, doors and windows are the most important thing to improve indoor heat and light environment, and their performance directly determines the effectiveness of building energy conservation. Enhancing the thermal insulation performance of doors and windows and reducing the energy consumption of doors and windows is an important step to improve the heat and light environment quality of buildings and achieve energy saving goals in buildings.

The insulation and heat insulation of doors and windows are closely related to the materials, structure and airtightness of glass, door and window frames. No matter what form or material is used for building doors and windows, glass is used. It accounts for more than 70% of the area of the window glass. Therefore, the energy saving of building doors and windows should first consider glass factors. This is why in the local laws and regulations that have been promulgated in major cities such as Beijing, Tianjin and Shanghai, the promotion and enforcement of energy-saving buildings has been vigorously promoted, and the reasons for hollow, inflatable, and low-emissivity glass have been promoted without exception.

The promotion and use of insulating glass is a symbol of the progress of the times, and the development of building energy conservation is dictated by the development. Insulating glass is sealed by two or more layers of glass and filled with an inert gas with a large viscosity coefficient and low thermal conductivity to reduce the convective heat transfer in the interlayer. Thermal coefficient K (refers to the heat transfer rate of 1 m2 of insulating glass per unit time when the air temperature difference between the two sides of the glass is 1°C under stable heat transfer conditions, expressed in W/m2K. The lower the K value, the lower The better the thermal insulation performance of the glass is 2.7~3.3, while the ordinary single glass is 5.8.

Of course, if the insulating glass can be matched with LOW-E or SUN-E glass, the thermal insulation performance is more outstanding due to its excellent optical thermal characteristics. In developed countries, insulating glass has been widely promoted and applied. The application penetration rate in the United States has reached more than 83%. The German government did not approve the construction of buildings without insulating glass. In the 1980s, the Federal Republic of Germany used hollow glass to reach 210 million square meters, saving energy costs of 5.2 billion marks. The application penetration rate in European countries has reached 50%.

In view of the fact that the production technology of insulating glass is quite mature, its practical use is extensive, its energy-saving effect is obvious, and its investment is not much increased. Therefore, the energy saving of building doors and windows has entered the era of insulating glass in the world, and it is also based on this.