- ClearPoint™
   - CyberShield™
   - Insulating
   - Insulating Laminated
   - Laminated Insulating
   - Double Laminated Insulating
   - Triple Insulating

   - Coatings
   - Glass Substrates
   - Heat Treatment
   - Spacer
   - Silicone
   - Interlayer

   - Argon
   - DigitalDistinctions™
   - Edgework
   - Holes
   - Notches
   - Silk-screen
   - Spandrel

   - Solar
   - Acoustic

   - BIG Glass




Now Available in BIG Glass Configurations.

An insulating glass spacer is placed within the unit to separate the two or more plies of glass. Viracon’s insulating glass spacers are available in two colors, three materials and a variety of thicknesses. When specifying an insulating glass unit, it is necessary to specify all three; color, material and thickness.

Color choices include a black painted finish or a mill finish which has a silver appearance. Mill finish spacers can be seen in the majority of existing buildings as they were the standard in the glass industry for many years. The trend is moving however to black painted spacers as designers see the clean look this option provides. The black tends to blend with the gaskets and framing which minimizes the overall visual impact by leading occupants to look through the glass rather than at the framing or spacer. The color of the spacer does not affect the solar performance of the insulating glass.

The thickness of the spacer will determine the distance, or space, between the two glass plies in an insulating unit. Viracon’s typical 1” insulating units are constructed using a 1/2” (13.2 mm) nominal thickness spacer, however a wide variety of alternate thickness spacers is available. Even a minimal change in the thickness of the spacer can affect solar performance so it is important to include the thickness in a specification.

Spacer Thickness


When selecting a spacer material it is necessary to be aware of the different u-values used in the glass industry. Center-of-glass (COG) u-values represent the center of the glass. Center of glass values provide an effective way to directly compare glass products without bias from spacer material, framing or unit size. Edge-of-glass (EOG) values represent the perimeter of the glass unit affected by the spacer material. Framing the glass unit is installed into also has a separate value. The three of these values are weighted based on the area of the unit to provide an overall u-factor. The overall value is typically an input needed to run whole building energy calculations and determine code compliance.

Aluminum, Stainless Steel and ExtremEdge™ are the three spacer material options available from Viracon.


Although aluminum is the most specified, increasing energy requirements are escalating the demand for alternate spacer options to improve edge of glass (EOG) u-value. Spacer materials that improve the EOG u-value beyond the performance offered by aluminum are commonly grouped together under the category of warm edge spacers or warm edge technology.


  • Aluminum has historically been the most-used spacer because of its malleability and availability.
  • Stainless steel is one warm edge spacer option offered by Viracon. Stainless steel is less conductive than aluminum and has one-tenth the thermal conductivity of aluminum.
  • ExtremEdge™ is Viracon’s newest warm edge spacer offering. The ExtremEdge™ spacer consists of a biopolymer in the cross section area which is encapsulated in stainless steel. This combination further reduces the edge conductivity and thus reduces heat transfer into the building.



Please use this chart as a guideline when selecting spacer color, material and thickness.

Spacer Availability


  • ExtremEdge™ can be used in spandrel applications.
  • Black painted and black anodized finishes are interchangeable.


Spacer materials that improve the u-value beyond the performance offered by aluminum are commonly grouped together under the category of warm edge spacers or warm edge technology. Below is an example of the improvement in thermal performance that can be obtained by using Viracon's warm edge spacers: ExtremEdge™ and Stainless Steel.

  1. Center of glass u-value is calculated using WINDOW 7.0.
  2. Rough opening u-value is generated by an NFRC certified simulator using THERM 6.3 and WINDOW 6.3 based on NFRC Standard 100-2010 in a thermally enhanced framing system.
  3. Condensation Resistance (CR): A relative indicator of a fenestration product’s ability to resist the formation of condensation at a specific set of environmental conditions. The higher the Condensation Resistance value the greater the resistance to the formation of condensation.