Insulated Glass, often called double glazing, is a combination of two or more panes of glass spaced apart with a spacer bar and hermetically sealed with a primary and secondary sealant to form a single unit with one or more air spaces in between. IG units improve the thermal performance, thus significantly reducing heating and air-conditioning costs. IG units also reduce probability of condensation formation on the surface of the glass.can be a combination of Low-E coatings, tinted glasses, reflective coatings, silk-screened patterns, laminated glass products and more. A wide variety of insulating glass configurations are available to satisfy a variety of performance and aesthetic requirements.