Window glass - which types are used?

Window glass is used in many different ways, each of which fulfills special functions and is used in various special areas. The most important window glass types and their properties are presented in detail in this article.

Low-E glass

This specially coated type of glass has been available in almost all insulating glass windows since the mid-nineties. It is a specially coated thermal insulating glass.

Low-E stands for the English word "low emmissivity" and means something like "low radiation". Low-E glass is coated with special polished metals or metal oxides, which emit less heat energy than glass itself.

The principle of this glass has long been known from Thermoskannen ago. In the window area, however, it is only used in the last 20 years. The highly integrated coating for the sun's rays also ensures a high degree of overall energy transmission.

Displacements in the range of visible light, as seen in sunglasses, are also prevented by the low-E coating. The disadvantage of low-E coating is the attenuation of radio waves. (In case of poor mobile phone reception, open the window).

A special version of the coating also makes it possible to produce solar control glass.

Solar control glass

Solar control glass can either absorb or reflect incoming sunrays. The mode of action is determined in each case by the type of coating.

Absorbent glass usually contains iron or copper coatings. By contrast, metallic dielectric semiconductors are used for a reflective layer.

Solar control glass is used primarily to prevent overheating of rooms. This succeeds to a high degree. Sun protection lenses are very powerful. The light transmission of these glasses is still between 50 and 70%. Ordinary heat-insulating glazing transmits about 80% of the incident light.

Alternative: sunscreen films

A similar effect can also be achieved by the gluing of sun protection films on the window outside. These easy-to-install films also hold between 80 and 90 percent of the incoming solar heat from indoor spaces. They are relatively inexpensive and have a lifespan of up to 10 years.

safety glass

Safety glass consists of several layers glued together (laminated glass or laminated safety glass). This glass is breakthrough and breakthrough. The performance is determined according to DIN EN 356 according to certain resistance classes (P1A - P8B).

Alternatively, the same protection can be retrofitted with protective films, but up to a maximum of resistance class P3A.

Self-dimming glass

Glass, which itself dims depending on the temperature or solar radiation, or can be switched electrically, is called "Smart Glass". The technology has long been known for sunglasses, and has been used in window construction for several years. At prices of around EUR 700 per m², the technology is currently still relatively expensive. However, an allowance for the mass market is already being worked on with financial support from the federal government.

The switching of self-dimming glass can be done in several ways:

  • in thermochromic glass automatically by heating the glass surface
  • for electrochromic glass, by applying or reversing a minimum voltage
  • alternatively also automatically via temperature sensors, light sensors and control units

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