Insulating Glass increases a window's thermal performance. At Viracon, Insulating Glass units are constructed with two or more plies of glass, separated by a desiccant-filled spacer and sealed with an organic sealant. The desiccant absorbs the insulating glass unit's internal moisture. The sealant may be the standard black silicone and PIB or you may choose a gray silicone/PIB sealant. Viracon uses mill finish and black painted spacers and also offer a stainless steel spacer for warm edge performance.

You'll find you can chose from over 350 combinations of Insulating Glass using tinted glass, silk-screened patterns, Low-E and solar reflective coatings to help you create unique designs and achieve specific transmission levels and solar control options.

Viracon's Solarscreen™ High-Performance
Reflective Insulating Glass
This type of glass combines the thermal advantages of insulating glass with the superior solar control characteristics of Solarscreen reflective coatings.

Viracon's Solarscreen Low-E Insulating Glass
When applied to a variety of glass substrates, Viracon's Low-E coatings offer a balance between light transmission and solar energy control.

Each coating offers high visible light transmittance, low exterior reflectance and the lowest U-values available; thereby, reducing radiant heat transfer.

By combining tinted glass with silk-screened patterns and Low-E coatings, the building design professional can achieve unique, custom glass designs.


Viracon Radiant Low-E (VRE) Insulating Glass
Viracon's VRE high performance coatings allow designers to balance aesthetics, reduce solar heat gain and bring in natural light. VRE coatings also provides a crisp neutral exterior appearance and soothing tones to the interior, allowing two-way vision through the glazing under varying lighting conditions. In addition, VRE coatings feature an efficient blend of U-values as low as any coating along with reduced solar heat gain not previously available with Low-E products.

Commercial Applications
Many commercial building designs feature large ratios of glass-to-wall areas, which translates into a greater potential for increased heat gain. What's more, secondary sources, such as people, office machines and artificial lighting generate heat within a building. Consequently, the emphasis is on reducing heat gain into the building interior.

Low-E coatings on tinted glass play an important role in thermal performance by possessing high visible light transmission and low heat transfer properties. What's more, Low-E coatings on tinted glass reduce glare.

When short-wave solar energy (IR) strikes the tinted exterior glass ply it is absorbed and converted into long-wave infrared or heat. By applying a Low-E coating to the second surface, the heat is reradiated back outdoors, reducing the heat gain potential into the building interior (see Figure).

Vision/Spandrel Match
Often a project may require spandrel glass to harmonize with the vision areas of your building. However, this is sometimes difficult to achieve when high-light transmitting or low-reflective glass types are used. Instead, the use of low-light transmitting and high-reflective glass types provide the least contrast between vision and spandrel areas under a variety of lighting conditions.

In addition, variable sky conditions can also influence our perception of glass color and general appearance. On a bright, sunny day, the exterior light intensity is approximately 50 to 100 times greater than the interior lighting level. When viewing the glass from the outside, the dominant visual characteristic is the exterior reflection. On gray, overcast days, a greater visual disparity is created between vision and spandrel areas.

This is due to the transparency of the vision glass and the perception of depth created by interior lighting. The non-vision areas tend to look flat and two-dimensional by contrast.

Because spandrel glass is virtually opaque, it can only be viewed in reflection. On the other hand, vision glass possesses a degree of transmission. As the transmission of the vision glass increases during overcast conditions, interior lighting becomes more prevalent. Viracon recommends viewing glass samples or full-size mockups to match vision and spandrel glass areas when the vision glass light transmission exceeds 14 percent.

Greater contrast between vision and spandrel areas occurs when using uncoated, tinted glass (green, bronze, blue, etc.) or high transmission Low-E coatings. Under these conditions, insulating spandrel units can create the illusion of depth and approximate the vision glass more closely. By keeping the vision and spandrel glass construction similar (the same exterior glass color, coating, etc.), the contrast can be minimized under various lighting conditions. Viracon recommends a neutral colored ceramic frit on the number four surface.