Glaze, a glass coating material, can be very useful for more than just protecting your windows from damage. Gazed windows can help with insulating a house. Glazing the windows in your home can prevent heat from entering or leaving your home. By adding gases such as argon or krypton you can strengthen your glass and the glaze applied to it. In multi-paned windows, multiple layers of glaze are applied to ensure that the entire glaze is firmly set in place. Glazing used to be done with things called glazing bars separating panes from each other while being glazed. Now instead of being for practical use glazing bars are used for decorative purposes.