An ongoing issue with new construction is the occurrence of window defects. Most newly installed windows are insulating glass (IG). These windows are have two panes with an air gap, and therefore, have 4 glass surfaces (surface #1 is on the building exterior) that may have defects. In addition, many have a coating on one interior surface (Low-E) to block infra-red light from entering and heating the building interior. This coating may have defects. When analyzing defective windows it is useful to use magnification to examine them. Magnified images have a narrow “depth of field”. This allows one to look through the glass and identify which surface of the IG unit has the defect.
