Vacuum glazing is a type of window glass that is super insulating. It has a very narrow gap between two glass panes that is vacuum-sealed, reducing heat transfer. Recent research has focused on using vacuum glazing in new and existing window constructions. The main goal is to reduce heat flow through windows. Two approaches were explored: using vacuum glazing in new windows and retrofitting existing buildings with it. The findings show that vacuum glazing can significantly improve the thermal performance of windows, making them as efficient as triple-glazed windows. It also offers a solution for preserving the appearance of historical buildings while improving energy efficiency.