Volume 7, Issue 11 - December 2006

Holistic Performance Defines Today’s 
Highest-Performing Spacer Systems

by Jeff Lehman

While it may seem odd to mention warm-edge IG spacer performance and golf in the same breath, an interesting parallel does exist. Most golfers know how challenging it can be to lower their average golf scores by even one or two strokes. But fix a minor swing flaw, try a new putting stroke or alter your practice routine even a little, and suddenly, a few small changes can yield noticeable improvements on the scorecard.

It’s no different in today’s highly competitive and commoditized window industry. As pricing pressures and energy costs continue to rise, manufacturers throughout North America are compelled to offer dealers and glazing contractors component products with tangible benefits to the bottom-line. Consequently, they now look to window component manufacturers that can provide real advantages – whether they are higher performance, improved aesthetics and product uniformity or superior long-term durability. 

Warm-Edge Spacers and Efficiency 
Warm-edge IG spacers have gained prominence in today’s market as manufacturers seek to meet these objectives. Today’s warm-edge spacer systems are highly efficient and light years ahead of those that dominated the market 10 years ago. Their effect on window performance can be significant. Just as new golf equipment by itself cannot turn a weekend golfer into an accomplished professional, spacers alone aren’t the sole determining factor of a window unit’s thermal and structural performance. But the highest-performing spacers – those with the warmest edge, and the greatest degree of structural rigidity, durability and manufacturing flexibility – will help window units achieve an added level of performance that set them apart in the marketplace. 

As energy prices continue to rise, consumers will continue to demand products that are energy efficient. At the same time, spacer systems must, over time, meet new, more stringent energy performance requirements that will most certainly be mandated by federal and industry regulators. Similarly, market expectations, litigation and risk management have encouraged component, IG and window manufacturers to anticipate tougher durability standards than in years past. However, when evaluating the comparative thermal performance of one spacer system over another, many IG and window manufacturers rely on sightline temperature as the key initial consideration. While sightline temperature is indeed a critical benchmark, we believe that a spacer’s holistic performance – its bundle of attributes – remains the best way for manufacturers to choose a spacer system that delivers the tangible bottom-line benefits both they and their customers demand.

Characteristics to Consider When Choosing a Spacer
Therefore, window manufacturers who seek a competitive edge should consider the following spacer attributes collectively when evaluating the best solution for their particular application:

Sightline Temperature
Today’s homeowners place increasing demands on manufacturers to offer windows with increased viewing areas, lower unit U-values, better condensation resistance and warmer sightline temperatures. Ten years ago, the term “warm-edge” spacer meant a more thermally efficient spacer than aluminum box. Now, the market defines warm-edge as anything warmer than stainless steel. Additionally, new “hot-edge” spacer systems featuring advanced materials enable high levels of performance that were unattainable in the past. 

Still, medium-performance warm-edge spacer systems dominate today’s residential IG market. That’s why, when evaluating sightline temperature performance, it’s essential to consider both the material composition of the spacer and its location relative to the edge of the glass. The sightline temperature determined by the combination of these variables helps to yield greater thermal comfort, lower condensation resistance, greater U-factors and higher energy savings.

Structural Rigidity
Some might argue that a spacer’s structural rigidity matters more for commercial applications than for residential. However, residential IG requirements include a higher percentage of glazing area per home, and larger unit sizes—up to 60 square feet in some cases. Managing these larger frames during IG unit assembly requires a rigid spacer. Otherwise, IG unit quality will suffer. Therefore, a spacer system should ideally offer commercial-grade structural rigidity in order to provide exceptional unit durability.

Gas Retention
IG manufacturers work hard to ensure that they’ve filled their units properly. Yet proper gas filling remains one of the industry’s leading worries. The best way to minimize gas loss is to have a continuous metal layer on the back of the spacer and a primary sealant that conforms to varying glass surfaces, especially custom-tempered glass. Currently, though, no official North American standard exists for gas retention. The world’s toughest gas certification test is the EN 1279 Part 3, in which an IG unit is filled to 90 percent and put through a chamber that simulates 10 years of use. Acceptable levels within this test allow one percent gas loss per year for 10 years. Therefore, look for a continuous spacer system that has passed as many components of the rigorous EN 1279 testing as possible, but particularly the stringent Part 3. Additionally, use care when selecting materials and choose only those that are proven to stand the test of time.

Precise Muntin Placement
Consistent, precise and positive placement of muntins is key to a window’s aesthetic appeal and provides ease in the manufacturing process. Yet some residential spacer systems don’t allow it. The cost of reworking IG units in which muntins were placed improperly is a hidden cost of some spacer systems. Additionally, muntins that are not mechanically attached to spacer systems can work loose during transportation. Therefore, it’s important to choose a spacer system that can be punched or drilled, depending on your preference, so as to provide a perfect fit every time. 

Aesthetics and Color Options
Varying interior and exterior color options is a significant trend in residential windows, especially in premium remodeling and new construction segments. Some spacer systems offer a range of choices to fit the marketing goals of the window aesthetics that manufacturers are trying to achieve. Ultimately, spacer systems should offer both desired performance and aesthetic attributes, and complement the look of the window. Therefore, look for a spacer system that offers a range of color options, straight sightlines and uniform corners and a finish that complements the look of the window frames.

Easy Manufacturing Integration
The cost to change a spacer system can involve significant capital expenditures. Some high-performing spacer systems allow the use of existing IG manufacturing equipment already in use on the shop floor. This helps to minimize the overall cost of conversion and allows an instant product upgrade to IG and window manufacturers. These spacer systems should also offer the ability to make special-shaped IG units as well. 

Remember, today’s best-performing spacer systems bundle the above-stated attributes together and, in turn, help to improve the performance of the window systems in which they are installed. Just as a new driver or a timely tip from a pro can help golfers achieve lower scores, spacer systems that feature a comprehensive bundle of attributes allow window manufacturers to offer unparalleled levels of performance, aesthetics and long-term durability. And in the end, isn’t that what builders, architects, designers and homeowners truly value?

Jeff Lehman serves as Technoform’s I-Spacer sales and marketing manager for North America.


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No reproduction of any type without expressed written permission.