How double glazing works.?

Double Glazing Stops Conduction and Convection but not radiation because you can see through glass: Double glazing keeps your house at a constant temperature because there is a vacuum in between two layers of glass. There is no air or particles of any kind in a vacuum, so heat cannot be conducted through it. Therefore the heat inside the building cannot be lost to outside, and vice versa.

Windows are designed to let in light, while blocking air and objects from entering the house. In addition, Windows provide some insulation, but not much. Windows are only a few millimeters thick, and heat can easily flow through them, making it more expensive to heat and cool your house. Double glazed Windows are designed to let light through while blocking the movement of heat, turning your Windows into good insulators.