Hansons Home Improvement Glass Glossary

Glass Glossary

Annealed Glass
Non-tempered glass. The most common glass used in window products.

Argon Gas
Replaces the air inside the glass unit. Since it is heavier than air and is not in continuous motion like air, the transference of heat and cold (convection) is greatly reduced. Argon gas is inexpensive, nontoxic, non-reactive, clear, and odorless. In essence, the Argon gas provides extra insulation.

Double Glazing
In general, two thicknesses of glass separated by an air space within an opening to improve insulation against heat transfer and/or sound transmission. In factory-made double-glazing units, the air between the glass sheets is thoroughly dried and the space is sealed airtight, eliminating possible condensation and providing superior insulating properties.

Bronze Tint
A smoky, subtle medium brown color designed to reduce solar heat gain and glare.

Gray Tint
A medium gray color designed to reduce solar heat gain and glare.

Hard Coat Low E
Hard coat Low E, or pyrolytic coating, is a coating applied at high temperatures and is sprayed onto the glass surface during the float glass process and is considered to be a medium performer. Hard-coat Low "E", one of the earliest coating types, reduces heat loss versus clear glass, and allows a high level of solar heat gain. It is most appropriate in climates where solar heat gain is desired.

Heat Absorbing Glass
Types of glass containing minute particles of metal that absorbs solar heat and is primarily used in commercial applications.

Heat Mirror®
A low-emissivity coated film product suspended inside an insulating glass unit. The result is a triple unit with two airspace's without the weight of triple insulating glass and with far superior insulating and shading performance.

Heat-Strengthened Glass
This glass is produced in much the same way as tempered glass, but with lower levels of surface compression, 3500-7500 psi.  The final product is two times ber than annealed glass.  The break pattern varies with level of surface compression with lower levels having a break pattern similar to annealed glass.  And higher levels resulting in patterns similar to tempered glass.

I.G. Unit (Insulating Glass Unit)
Two or more lites of glass separated by a spacer and hermetically sealed at the glass edges.

Laminated Glass
Two or more sheets of glass with an inner layer of transparent plastic to which the glass adheres if broken. Used for safety glazing and sound reduction. Low-E Glass
A common term used to refer to glass, which has low emissivity due to a film or metallic coating on the glass or suspended between the two lights of glass to restrict the passage of radiant heat.

Obscure glass
Any textured glass (frosted, etched, fluted, ground, etc.) used for privacy, light diffusion, or decorative effects.

R-Value
Resistance to thermal transfer or heat flow. Higher R-value numbers indicate greater insulating value.

Single-Glazed with Clear Glass
Single-glazed with clear glass allows the highest transfer of energy (i.e. heat loss or heat gain depending on local climate conditions) while permitting the highest daylight transmission.

Solar Heat Gain Coefficient
SHGC, is primarily used in southern climates and measures the amount of solar radiation transferred through the windows to the interior of a home.  The lower a window's solar heat gain coefficient, the less solar heat is transmitted.

Soft Coat Low E
Soft coat Low E, or sputter coating, is applied in multiple layers of optically transparent silver sandwiched between layers of metal oxide in a vacuum chamber. This process provides the highest level of performance and a nearly invisible coating.

Tempered Glass
A type of safety glass that has been heat treated so when it breaks it separates into very small pieces that reducing the possibility of injury. Tempered glass is used in doors, windows located near doors, and other locations where safety is critical. Glass tempering is achieved by heating annealed glass to near it's softening point, rapidly cooling the surface and allowing the inner core to cool naturally. The result is layers of high compression at the surfaces balanced by a high-tension layer through the center of the glass making it much ber than annealed glass. Once tempered, the glass will fracture if cut.

Tinted Glass
A special type glass with additives, usually metallic particles that reduce the passage of sunlight. Tinted glass can be bronze, gray, green or blue as well as other more exotic colors.

Triple-Pane Glass
Manufactured like double-pane, but with an additional airspace. The two air spaces created by the panes of glass greatly slow the rate of conduction and heat transfer, increasing the R-value to keep your home much more energy efficient. Similar efficiencies can be achieved with modern day low E coatings or Heat Mirror at a much-reduced cost.

U-Factor
U used primarily in northern climates, is the measurement of heat loss through a window.