Surprisingly, no glazing is vacuum sealed mainly because it would set The 2 panes of glass under pressure and at some point the two panes would contact. Manufacturing unit fitted double glazing is hermetically sealed, indicating that no air can enter or escape. A 20mm translucent standing seam polycarbonate system. https://rylanidvjw.techionblog.com/34781021/considerations-to-know-about-heat-loss-prevention