Energy Efficient Window Glass Spacers

Window and glass spacers are the seals that sit between panes of glass in a window.  Over the years, the window manufacturing industry has seen quite a swing in terms of materials and technologies used to make window glass spacers.

  As the push to create more energy-efficient home-building materials increases, more and more manufacturers are turning to new types of glass spacers to boost the “greening” of their products.

The material used to manufacture the glass spacer is one of the most important factors in whether a window is energy efficient.  Glass spacers play an important part in a window’s overall performance in this area, as they determine the amount of heat and cold that is able to pass through a window’s panes.

Panes of glass in insulated glass are held apart by spacers. Spacers impact the overall performance of the insulated glass. The quality of the materials used to produce spacers, their longevity, flexibility and thermal properties are critical. 


Why is spacer so important?

On the outside of your home, windows have to stand up to the extreme weather conditions all year round. They face changes in temperature, wind loads, barometric pressure. Additionally, windows are bombarded with harmful UV rays from the Sun. On the inside of your home, windows have to face changes in temperatures, too. And because the edges of the insulated glass are the coldest parts of the window, they are the most susceptible to condensation. Condensation most often occurs in well insulated and weather tight homes. Not only can window condensation lead to damaging your woodwork and draperies but also it can fuel mold growth. 

Good spacer should do 4 things:

  • Absorb stress caused by thermal expansion and contraction
  • Block moisture and water vapor that can fog glass
  • Create a tight seal that prevents leakage of special gas fills
  • Increase the temperature of the edges of the insulated glass – this can help reduce condensation and increase overall energy efficiency of the window

Never overlook the spacer used in your window. Period.

Older double-pane windows used metal spacer, typically aluminum. Problem with aluminum is that it is an excellent conductor of heat and cold. During winter it conducts cold and makes the edges of the glass even colder. This decreases overall U-Factor of the window making it less energy efficient. In addition to the increased heat loss, the colder edge is more prone to condensation. Also, aluminum spacer is usually square-shaped. This inflexible shape is typically a major reason for seal failures and foggy windows. 

PPG Intercept Warm Edge Spacer

To address the problems of aluminum spacer, in 1992 PPG introduced Intercept Warm Edge Spacer. Intercept features a unique, one-piece stainless steel alloy that creates an effective thermal barrier to help reduce conducted heat loss. This keeps the edges of glass warmer, too. U-shaped flexes and resists seal failure. 

Intercept spacers flex instead of the sealant during temperature changes. So they resist spacer movement and sealant failure.
With conventional aluminum spacers, the sealant flexes, which can lead to sealant failure and loss of insulation ability.

PPG Intercept spacer features “Warm-Edge” technology that reduces condensation problems around the window perimeter. Compare the Intercept insulating glass window (below left) with a conventional insulating glass window (below right). Both windows have LowE glass and argon gas. The difference is in the spacer. 

With Intercept Spacer        vs. With Aluminum Spacer

Condensation and window edge.

This thermal picture compares room side glass temperature for an Intercept insulated glass (left, yellow is warmer, blue is cooler), and a conventional aluminum spacer (right). Since the Intercept allows for significantly warmer glass temperature especially at the edges, your home will feel more comfortable. 

Glass temperature at window edge.


  • Cold side temperature = 0 F
  • Room side temperature = 72 F
  • Cold side relative temperature = 25%


EdgeTech SST Foam Super Spacer

EdgeTech company went step further and designed foam Super Spacer. The SST Spacer System features a non-metal design that eliminates cold-edge metal-to-glass construction at the glass edge. This ensures greater insulation at the glass edge – where the window traditionally insulates least effectively – and virtually eliminates condensation at the edges of the window associated with metal spacers that conduct cold air.

*Test Values were determined with VISION 4.0 program using standard boundary conditions. 
Configurations were determined by the manufacturer. Cavity width modified to conform with spacer manufacturers’ tolerances.

What is Super Spacer?

Standard windows use a highly conductive metal spacer bar to hold the two panes of glass apart, which sucks heat from inside to the outside. Super Spacer introduces no-metal warm edge technology to windows, helping to deliver windows of the highest standards. Super Spacer® is a no-metal, pre-desiccated, structural foam spacer system. Its award winning, patented Thermal Set Spacer (TSS) technology gives the ultimate in high performance spacer systems. Since it was first introduced in 1989, Super Spacer has become the dominant force in thermally efficient spacer systems.

Super Spacer has 100% memory and allows for expansion and contraction, a major cause of fractures in conventional sealed units. In accelerated testing Super Spacer has been shown to last over twice as long as other dual seal systems and five times longer than single seal systems.

Windows using Super Spacer achieve the highest Window Energy Ratings from the National Fenestration Ratings Council.

Most PVC-U and traditional timber windows include low line glazing beads and gaskets. This creates problems for standard aluminium spacer bars which protrude into the sightline of the window. Super Spacer has a lower sightline (equivalent to only 9.8mm from the edge of the glass) which eradicates the problem.

Super Spacer also takes on the appearance of the colour of the profile into which it is glazed. For example, if Super Spacer is glazed into white profile the spacer reflects back white. This eliminates the need to stock a wide range of different colors and simplifies ordering and stock control.

Top 5 Reasons Super Spacer Tops the Chart 


Reduces Sealant Stress

Super Spacer’s thermoset polymer material expands and contracts and always returns to its original shape. Super Spacer sealed IG units last up to five times longer in durability tests than conventional single seal units. 

Super Spacer features superior Argon gas retention

Super Spacer Warm Edge Technology


Improves Heat Flow Resistance

The all-foam formula blocks heat transfer and provides one of the best thermal performances available. Super Spacer resists heat flow 950 times more than that of aluminum. This means lower energy costs, less condensation/frosting and reduced chances for mold growth.

Heat Flow Super Spacer Technology


Improves Glass Surface Temperature

Super Spacer’s extremely low thermal conductivity means less variation in the surface temperature of the IG unit. 

Super Spacer units withstand 140°F/60°C temperatures, 95-100% humidity and constant UV bombardment in the world’s toughest durability test – The P-1 chamber.

Super Spacer Technology


Improves Sound Absorption

The closed-cell polymer foam in Super Spacer transmits very little sound compared to conventional aluminum spacers. 

Acoustical laminated glass, Super Spacer and varying thicknesses of glass are recommended wherever noise from airplanes, trains or automobiles are a concern.

Super Spacer Technology


Improves Condensation Resistance

Mold needs moisture to grow. Moisture can increase the likelihood of fungi, viruses and mites that can cause infections, allergies and asthma. The significantly reduced interior condensation or frosting means that the health problems associated with mold may be virtually eliminated.

Relax. We got you covered.

Because technology helps us do it.

Easy Windows & Siding offers only Preservation windows that utilize the latest spacer technologies. All ClimaTech glass packages feature PPG Intercept Warm Edge Spacer. This unique system will help you keep heating and cooling costs down, reduce condensation and boast long-life service of your insulated unit. Additionally, we offer ClimaTech PLUS featuring all-foam NO-metal Super Spacer. This sophisticated spacer system provides the warmest edge temperatures and dramatically reduces condensation. 

For higher energy savings and greater comfort choose Easy Windows & Siding, LLC. Do your research and let us know what technology works for you. Call us 216-232-8326 if you have any questions. We’re ready to help. 

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