When Good Windows Go Bad: Failed Window SealsWindows don't last forever. Roofing and siding have the longest-lasting warranties. They are assured to last for decades. Some roofing materials are warranted for 50 years.
Windows are subjected to the elements as much as roofing and siding materials, yet they are more delicately constructed. After all, we're dealing with glass, caulk, wood, vinyl, and metal. These things break down rather frequently.
It's not uncommon at all for a house to have at least one window with a failed seal. How can you tell, though?
Tips for Detecting a Failed Window SealOne certain way not to detect a failed window seal is by putting your hand on the glass. Unless it's 37 degrees below zero outside, it's doubtful that the "feel test" will work. Instead, examine the glass itself. Fogging, hazing, or moisture between the two panes of glass mean that a window seal has fogged. While a window can certainly fail and not have any moisture between the two panes, it's more common to see moisture between the two panes.
Don't jump to conclusions, though. Do your CSI work carefully. Clean the inside and the outside of the window so you're certain that you're not looking at external moisture. Also, sometimes the glass itself may be hazed through a failure of the glass or through overspray from painting.