WHAT ARE THE TERMS USED IN GLASS UNITS?
2-layer and 3-layer glass units.
In general glass units are two- or three-layered. What does it mean? Glass units have one or two glazing bars. If only one glazing bar is visible, it is a 2-layer glazed unit:
|There is one glass pane on the outside and the other one on the inside, the glass unit is therefore a 2-layer glass unit.|
|When there are two glazing bars next to each other, it is a 3-layer glass unit.|
|In this case in addition to the external and internal glass pane, there is also a third glass in the middle.|
A glazing bar is placed between the glass panes in a glass unit. Glazed bars are made of aluminium and composite material – in another words out of plastic alloy. Warm spacer glazing bar is more valuable and is more heatproof than aluminium, because in case of metal, there are bigger thermal bridges, which cause the glass panes in a glass unit to cool off. It can be observed when standing next to a window one feels coolness coming from the window.
A glass with low emissivity coating for better insulation:
A glass with low emissivity coating – low emissivity material with soft surface is added to the glass pane, which increases insulation of a window. A glass with low emissivity coating better reflects the interior heat back into the room. An internal low emissivity coated glass is usually included into the standard offer of our windows. Two low emissivity glasses are used in 3-layer glass units, where bigger insulation is required. In case of 2-layer glass unit, the use of two low emissivity glasses does not provide the same effect of insulation, as in case of a 3-layer glass unit.
The thickness of glasses used in glass units is normally 4 or 6 mm; less frequently, thicknesses of 8 mm or 10 mm are used. Thickness of 6 mm is usually used in large windows, because 4 mm glass would be too thin and would not ensure sufficient stability. Thicker glass units are not used for the following reasons: price is too high + weight of the glass is too heavy which cause the weight of the entire window become too heavy, which complicates the installation work and shortens the service-life of the window.