How Moisture Develops

No window is ever hermetically sealed. In fact if it was... it would explode!

Depending on the type of window, Window Medics International has found that, on average, 75% of failed windows do not have a seal failure but instead are simply fully saturated from years of Solar Pumping.

Solar pumping naturally occurs during the change from day to night. Sunlight heats the inner airspace of the thermal window cavity during the day and causes the window to pressurize, which forces out small amounts of air within the window cavity through the semi-permeable seal. In the evening, as the temperature drops, the window cools and creates a low pressure area causing small amounts of air to be drawn back into the inner window cavity. The air being drawn back into the window naturally holds moisture and this moisture is absorbed by the windows desiccant material.

Solar Pumping activity over a period of time saturates the Silica desiccant material in the thermal window cavity until eventually fog, condensation or moisture appear on the inside surface of the window. This moisture is trapped within the window and an endless cycle of heating, fogging, cooling, and condensing occurs.