What You Should Know Before Choosing Glass

Glazing has a significant impact on the overall performance characteristics of the product, and therefore it is essential to pay maximum attention to it when specifying windows and doors.

What are the basic parameters of glass and which performance characteristics of windows and doors do they affect?

1. The heat transfer coefficient Ug (W/m²K) has a significant impact on energy savings in heating.

2. The solar factor g (%) expresses the potential heat gains through glazing. When the value of this factor is too high, rooms overheat in summer. However, a solar factor value that is too low is not ideal either, because it deprives us of natural room heating from solar radiation in winter (heat gains). The value therefore tells us the extent to which the glass is able to protect us from heat gains from solar radiation on hot days and at the same time the extent to which it allows us to obtain heat gains from winter sunlight.

3. Light transmittance TL (%) indicates the extent to which glass allows light to pass into the interior and thus how well-lit the rooms will be.

4. The airborne sound insulation coefficient Rw (dB) indicates how well the glass protects us from noise.

5. Glass safety classes indicate the level of protection of the building against forced entry, protection of glass against firearms, and protection against fire.

What is the total energy balance of glazing?

It is a comprehensive indicator determined by the heat transfer coefficient Ug and the solar factor g. This means it is a balance between heat losses and heat gains. Through ideal glass, no heat should escape in winter and it should even help us heat rooms during sunny winter days, but conversely in summer it should not contribute to heating interiors. The total glazing balance tells us the extent to which a particular glass approaches ideal glass.

What is insulating glass?

In general, every insulating glass unit consists of two or three panes of glass that are separated from each other by a profile (spacer bar). The spacer bar is filled with a special material (molecular sieve) that has the ability to adsorb water vapor (i.e., moisture) and thus prevents its condensation in the space between the panes. The glass panes and spacer bar are joined together using double-sealing technology, which ensures high resistance of the glass to mechanical stress. The cavities between the panes are filled with inert gas (argon, krypton).

What does the degree of thermal insulation properties of insulating glass depend on?

• On the type of glass panes themselves and their composition
• On the type and properties of the low-emissivity (low-E) coating
• On the spacer bar, specifically its thickness, material, and properties
• On the type of gas between the panes

What is meant by the term “warm edge”?

Unfortunately, aluminum spacer bars are still used as standard, which, especially in winter, cause a thermal bridge due to their good thermal conductivity, which can result in the formation of condensation, particularly on the bottom edge of the insulating glass. A warm edge spacer is made of refined thermally non-conductive materials that create a “WARM EDGE” of the insulating glass, thereby significantly reducing the risk of condensation forming on the bottom edge of the glass. Moreover, the warm edge spacer significantly reduces heat losses through the edge of the glass and improves the thermal insulation properties of the entire structure.

At ALUPLAST s.r.o., we supply all insulating glass units as standard with SWISSPACER warm edge spacer bars (technical parameters here), or SWISSPACER Ultimate (technical parameters here)

What glass do we offer as standard?

Thermal insulating double glazing and triple glazing

• With low-emissivity coating (low-E), exhibiting improved thermal insulation properties while maintaining good light transmittance.

• Emissivity level of low-E coating = 0.01 and 0.03

• With warm edge spacer “warm edge” SWISSPACER, or SWISSPACER Ultimate

• Fill gas: Argon 90%

Comparison of parameters for standard double glazing and triple glazing:

A more detailed comparison of the parameters of our double glazing and triple glazing with SGG Planitherm XN low-emissivity coating can be found here.

What are the aesthetic options for glass?

Various types of decorative grilles can be applied to glass, or you can choose from a wide range of ornamental or patterned glass. These are important in creating privacy and intimacy in living spaces. Of course, they also significantly contribute to the design of the interior, exterior, as well as the window and door units themselves. We present only a small sample from the large selection of decorative glass. If you are curious about the full range and aesthetic possibilities of ornamental glass, read more here.

What are the functional options for glass?

Glazing can simultaneously meet various requirements, such as the requirement for a favorable energy balance, protection against forced entry, personal injury, sun, UV radiation, or excessive noise, the requirement for a self-cleaning glass surface, privacy protection (opacity), aesthetics (ornamental, patterned glass), and many others. Sometimes it is difficult to fit multiple properties into the composition of a single multifunctional glass unit. However, we can offer you expert advice in this regard and select the composition that will best suit your needs.