[MRM]

A few years ago there was a defect in the glass produced by the company that supplies most of the glass used in residential windows. It affected the entire industry. Andersen sourced their glass from the same company so there is an era of Andersen windows that is prone to seal failures and losing the argon gas. Apparently argon has extremely small molecules. The elements in air have larger molecules. The coating on the glass was porous enough that the argon could escape as the gas heated and expanded, but the larger environmental molecules were too big to replace the argon. Eventually a vacuum forms and the seals can break. In extreme cases the window itself can break. I knew a house (not with Andersen windows) where the homeowner kept getting broken windows. He thought he was being targeted by some hate group or something. Eventually the window repair guy was in the house as a window broke and he was able to track the problem down.

With the larger reputable companies seal failures are 100% covered by warranty and changing our the sash is a piece of cake.