because they are good insulators
The advantage of double glazed window units is how well they are able to insulate a house. A double glazed window unit can actually save a household hundred of dollars every year in electricity.
double glazed
Removing draughts Lowering the conduction across the window glass surfaces (the air gap acts as a thermal insulator) Some double glazed windows have coating that reflect infrared light back into the room.
The percentage insulation witha double glazed window, as oppsoed to a single glazed window is about twenty three percent less. This makes it very energy efficient.
double glazed windows
Installing a double glazed window in a home can provide benefits such as improved insulation, reduced energy costs, noise reduction, and increased security.
Almost 1/2".
The U value of a double glazed window is a measure of how well it insulates against heat transfer. A lower U value indicates better insulation, meaning less heat is lost through the window.
The R value of a double glazed window is a measure of its thermal resistance, indicating how well it insulates against heat transfer. A higher R value means better insulation.
Installing double glazed window glass in a home provides benefits such as improved insulation, reduced energy costs, noise reduction, increased security, and enhanced property value.
I presume you are talking about Georgian Bar, a pattern of fixed bars between two panes of glass in a double glazed window unit.
it slows conduction