Technical information



U-value – heatproof
Heatproof of windows is calculated by U-value, which is between 0.7-1.0 for modern high-quality windows. Mainly, it depends on the type and size of a window and components of glazed unit. The lower the U-value, the higher the heatproof. U-value (Uw) of a window shows how many watts per hour and per 1 m2 exits through a room provided that the external temperature is 1 degree lower than internal temperature.
G-value – solar control
The temperature of a room may rise very quickly in spring and summer due to a large amount of solar radiation. The amount of energy needed to cool down a building which facade has a big glazing may even exceed the amount of energy needed for heating during wintertime. If the temperature is to be kept low, solar control glass should be used. These are usually with a special coating. solar control glass shall ensure a good heat insulation (low U-value) and a low amount of solar power entrance to the room simultaneously.
Solar control is indicated by the g-value or Sf-value. The greater the G-value, the stronger the so-called greenhouse effect. The smaller the G-value, the more stable the temperature of a room.
LT – light transmission
Shows the amount of visible light transmitting the glass in percentage.
UV - Invisible short wave in percentage, which can lead to fading and aging of materials.
Rw, Rw+Ctr - sound insulation
Using sound insulation windows for constructions near busy street, railway, airport or highway makes sense. Sound insulation of a window depends on the following factors:
- As wide jamb as possible in twin sash window where frames are as far as possible from each other;
- difference of glasses thickness and as thick as possible: assembly from glasses with different thickness and asymmetric construction intensify sound insulation;
- Lamination of glasses – two or more layers of glass are used in a laminated glass.
In the light of sound insulation, the best solution is to use special sound insulation film. Sound insulation of a glass is measured in Rw-value (in decibel, dB) of sound insulation index. The greater the value, the better the window is insulated from noise by glass.