glass unit replacement 3

https://astro-wiki.win/index.php/Why_Argon-Filled_Windows_Are_Worth_the_Investment_for_Dallas_Homeowners

When the glass in a double-pane window gets foggy or cracked, it's often cheaper to replace just the glass unit rather than the whole window frame. A glazier removes the sash, takes out the old sealed insulating glass unit, and installs a new one with fresh perimeter seals.