How does Double Glazing work?

Windows are designed to let in light while blocking air and objects from entering the house. Besides, windows provide some insulation, but not much. Windows are only a several millimetres in thickness, so heat is able to freely move through the panes, resulting in higher energy costs for heating and cooling your home. Double glazing is designed to let through the light while blocking the movement of heat, converting your window into a good insulator.

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Double glazed windows have two panes of glass separated by a layer of trapped air. The gap between the windowpanes is insulated well so that no or hardly any air can leak between the panes of glass. As well as this, there can sometimes be a dryer between the panels to absorb moisture and stop stray mist from forming between them. The window can be clear or coloured or covered with a reflective coating. For more information on Glass suppliers Bristol, visit a site like

Double glazed windows protect in several different ways. It has two glass panels doubling the amount of glass that heat has to pass, slowing movement and helping isolation. Actual insulation strength, however, comes from trapped air. Heat is the motion of the molecules – the hotter the material, the faster the molecules move. When the excited molecules bang into molecules nearby, they disperse heat in a process known as conduction. Due to the fact that air molecules are scattered, they are unable to perform anywhere near as effectively as denser gas. Consequently, the trapped air acts as an insulator. Some of the heat can still be flowing through the air but moves more slowly than it does through glass.

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Double glazed windows can also be improved by adding a coating. Different coatings are used for different purposes. For example, a metallic reflective layer outside the outer panel will stop the infrared radiation from passing through glass from the outside, to prevent the sun from heating the room. The same layer outside the inner panel, however, will stop the infrared leave the room, keeping it warm. Double glazed windows also can be tinted to reduce incoming light, like a normal window.