Double-pane windows have nitrogen gas or very dry air between the panes. Why is ordinary air a poor idea?
Solution 15E Step 1 of 2: Double pane windows are used at home, for keeping the home more energy efficient by trapping more heat inside during winter and more cool air inside during summer. During winter, the central heating system in home warms the inside environment of home to a temperature which is more comfortable than the outside environment cold temperature. But when the heat that has generated from the heating system, escapes through the window. The central heat system has to work more to maintain a stable temperature inside home, which in turn leads to higher consumption of energy. Conversely during summer. Thus double pane windows are used to prevent this heat loss by trapping heat between the two planes before it can escape to the outside environment, in other words, to avoid convectional heat flow.