When is insulating glass fogging not considered failure?
The appearance of condensation between the panes of an insulated glass (IG) unit is an indication the hermetic seal of the unit has been breached or compromised, thereby allowing outside moist air to infiltrate the air space where it condenses on the interpane surfaces of the glass. One could argue semantics, but this is the generally accepted meaning of the word “failure” as it relates to IG units. In this case, the failure is characterized by an ever-present condensation between the glass panes.