What Are Insulated Glass Units?

Insulated glass units, commonly called IG units, became options for homes in the 1960s. Considering today’s rising energy costs, insulated glass units are a viable way to lower energy bills while maintaining a consistent, comfortable temperature in homes and offices.

How Are Insulated Glass Units Made?

IG units are windows made from two or more lites of glass separated by a sealed air space. The metal tube around the perimeter of the insulated unit that separates the two lites of glass is called the spacer. This spacer comes in thicknesses of 3/16" and larger. It is filled with a special moisture-absorbing material called a desiccant. The perimeter of the entire unit is sealed with a high-grade sealant.

Benefits of Insulated Glass Units

IG units reduce the tendency of condensation to form on the room side of the glass. IG units also reduce cold transmittance at windows and helps maintain a uniform temperature in the home or office. In the winter, IG units reduce heat loss and in the summer they reduce heat gain. Although soundproofing is not their intended purpose, IG units can help reduce the level of noise from the outside, especially if the lites are laminated glass.

Different Types of Insulated Glass Units

There are two types of IG units commonly manufactured, Single Seal Units and Double Seal Units. The difference between the two, as their names suggest, is the presence of a single or double seal between the spacer and the glass. Single-sealed units can use several types of sealants: hot melt butyl, polysulfide, silicone, or urethane. Double-sealed units can use PIB tape for the primary seal and hot melt butyl (one part silicone, or two-part polysulfide) for the secondary seal.

IG units need not use the same type of glass. Tempered and annealed glass can be used in the same unit. Patterned glass can be used but the pattern should face the outside. If one of the lites is reflective or tinted glass, it must face the exterior. If reflective glass is to face the interior, it may be necessary to temper one or both lites to guard against thermal breaking. A sandblasted finish is not recommended for an insulated glass unit because sandblasting reduces the strength of the glass.

Have questions about an insulated glass project for your home or business? Contact your local Glass Doctor at 833-365-2927 for upfront pricing, expert workmanship and 24/7 emergency service. We fix your panes!®