The principle

Conventional IG unit consists of two parallel panes placed 6-12 mm apart, and the spacing gap between them is filled with a dry gas. The edge seal around the glazing is made with an organic sealant. The gas enclosed in this space (Air, Argon, Krypton, etc) reduces heat transfer through the glass for its low thermal conductivity.
However, in vacuum glazing extremely high thermal insulation effect is expectable by minimized heat flow due to the conductance and the convection using 0.2 mm vacuum spacing gap between two panes, and by the restricted heat transfer of radiation energy using Low-E glass.
Furthermore, for long term safety, the glass is designed with great care so as to resist the force of atmospheric pressure applied to ita panes.

Schematic diagram of vacuum glazing.

Schematic diagram of vacuum glazingFigure1 shows the structure. An array of support pillars (micro-spacers) with 0.2 mm thickness and 0.5 mm diameter is placed between two panes to maintain uniform vacuum space. Pillars are set 20 mm apart each other.
One of the panes is Low-E glass facing to the vacuum space. The edge of the glazing is sealed with solder glass, which has matched expansion coefficient to float glass.

Creating warm space/Thermal Insulation

In thermal insulation effect, Standard Vacuum glass is 4 times of single pane, and exceeds conventional IG unit

U-Value/m2ĚK) variuos types

ST (Standard)


Single pane


IG unit (FL3-Air6-Low-E3)


IG unit (FL3-Ar12-Low-E3)


Higher thermal performance gives rise to less heat loss through the window and less cold air down flow along the inner surface of the window glass. Figure 2 shows the glass surface temperature of Vacuum Glass and IG unit in thermo viewer photograph taken from outside. In Vacuum Glass, temperature is around 10.5oC to be about 2oC lower than that in IG unit. In this way, The Vacuum Glass presents you warm and comfortable space in the dwellings, restraining the unpleasant cold air down flow in room and requiring 15% less energy consumption than conventional IG unit.

Condensation free

Condensation temperature of Vacuum Glass in various outdoor temperature and different humidity in room

Condensation, one of the commonest complaints in daily life, contaminates walls and ceilings, damages window frames, aids in propagation of mold, and causes allergies. Vacuum Glass can significantly reduce the condensation on window glass due to its higher thermal performance as seen in Figure3.
In Vacuum Glass, no condensation can be seen up to -21oC, while it appears around 0 oC in conventional IG unit. Even at 80% humidity in room, Vacuum Glass enables to enjoy clear view through the condensation free window at 0 oC or below in outdoor temperature.

room temperature 20oC
wind velocity (outdoor) 3.5m
air flow in room natural flow

Sound reduction

Comparison of Vacuum Glass with other type of glasses in sound reduction effect

Comparison of SPACIA with other type of glasses in sound reduction effectOne of the features of Vacuum Glass can be seen in sound reduction effect as well. Different from conventional IG unit, its sound reduction level stays in higher performance even in low frequency range. Theoretically, Vacuum Glass's sound insulation can be regarded as that of single pane with the same thickness as Vacuum Glass.


Latest revision date: 16-08-2011




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