argon filled windows 2

https://papa-wiki.win/index.php/When_to_Choose_Glass_Replacement_in_Dallas:_A_Practical_Guide_for_Homeowners_and_Business_Owners

Argon filled windows use an inert gas between the panes to reduce heat transfer, which helps keep your home warmer in winter and cooler in summer without extra effort. Unlike plain double glazing, the argon layer cuts down on drafts near the glass, so you're less likely to feel a chill while standing by the window. It's a simple upgrade that many people don't notice until they compare energy bills—then it really stands out.