A thermal glass unit is like a small greenhouse. The air between the two panes can heat up dramatically when the sun shines on the glass. This causes changes of pressure between the panes which affects the humidity of the air inside.
When thermal glass units are new, water absorbing pellets in the frame absorb moisture. Over time, the pellets become waterlogged and no longer function. This allows the moisture trapped between the glass to evaporate and condense repeatedly. This eventually leads to scaling of the interior glass surfaces.
Our restoration process, which includes the installation of a micro-vent directly on the surface of the glass solves the humidity problem between the panes. What you end up with is a window which defogs itself and stays permanently fog free.
Once our technicians have done their work, the fluid dynamics within the glass unit are different.
The micro-vents become active when heat or sunlight increases pressure within the window causing the water vapour to escape through the micro-vents. Once the water is gone the pressure equalizes.