Glass units are composed of:
- glass panes
- sealed air/argon chambers
- spacer bars
- desiccant
- butyl sealings
- silicone/polysulfide sealings
As glass units constitute more than 80% of the window/door surface, their thickness and the type of glass used are very important.
Ug is used to measure the insulation properties of glass units. The lower the Ug values, the better the insulation properties of the glass unit.
Different glass types account for different Ug values resulting in better …
- UV and light protection
- Soundproofing
- Thermal insulation
- Stability
Glass units are made with two, three or more panes.
Double glass units ensure Ug values between 1.8 and 1.0 W/m²K.
In triple glass units the heat transfer coefficient is between 0.9 and 0.4 W/m²K.
The Ug value denotes the heat transfer from the inside of the room to the outside and is a function of the lost heat flow (expressed in Watts) for a certain surface area (in m²) and the difference between outer and inner temperatures (in Kelvins): W/m²K.
It depends on the individual heat transfer coefficients (U values) of the window frame, glass panes and sealings.
As a whole, the lower the U value, the better the insulating properties and the greater the energy saved.