Surprisingly, no glazing is vacuum sealed mainly because it would put The 2 panes of glass under pressure and sooner or later The 2 panes would touch. Factory equipped double glazing is hermetically sealed, indicating that no air can enter or escape. R-price unaffected by humidity : Stops condensation : https://whiteceilinglights26543.techionblog.com/34661826/about-double-glazing