When homeowners shop for new windows, they usually compare the glass package or the frame material. But one of the most important components of a high-performance window is rarely discussed—the insulated glass spacer.
The spacer sits between the two or three panes of glass in a double- or triple-pane window. Its job is to maintain the sealed airspace that provides insulation, keep moisture out, and help retain the insulating argon gas inside the unit.
When that seal fails, moisture enters between the panes, causing the fogging or rainbow effect shown in this photo. At that point, the insulated glass unit (IGU) cannot be repaired—it must be replaced.
Why Spacer Systems Matter
Not all spacers are created equal.
The type of spacer used during manufacturing can make a significant difference in the long-term performance and durability of a window.
The Problem with Traditional Metal Spacers
Metal spacers are still widely used throughout the window industry—even in some premium window brands. While they provide structural strength, they also conduct heat extremely well.
That creates several disadvantages:
• Increased heat loss during winter
• More heat transfer into the home during summer
• Colder glass temperatures around the edge of the window
• Greater potential for interior condensation
• More stress on the insulated glass seal over time
As temperatures change, the glass expands and contracts. Those repeated cycles place stress on the sealant system. Over the years, that additional stress can contribute to seal failure—the most common reason insulated glass units fail.
The Warm Edge Advantage
Warm edge spacer technology was developed specifically to reduce these problems.
Unlike traditional metal spacers, warm edge systems are manufactured from low-conductivity materials that dramatically reduce heat transfer at the edge of the glass. The result is improved thermal performance and less stress on the insulated glass unit.
Why Windowcrafters Uses DuraSeal Warm Edge Spacers
At Windowcrafters, every window we manufacture includes DuraSeal Warm Edge Spacers as standard—not as an upgrade.
1. Better Energy Efficiency
By reducing heat transfer around the perimeter of the glass, warm edge spacers improve the overall insulating performance of the window and help maintain more consistent indoor temperatures.
2. Reduced Stress on the Seal
This is one of the biggest advantages.
Unlike rigid metal spacer systems, DuraSeal is engineered to accommodate the natural expansion and contraction that occurs as outdoor temperatures change.
Rather than relying solely on adhesive, the spacer is laminated within the insulated glass assembly, creating a stronger, more durable bond that helps reduce long-term stress on the seal.
Less stress means a lower likelihood of premature seal failure—the leading cause of fogged insulated glass.
3. Long-Term Durability
Windows are exposed to years of heat, cold, sunlight, humidity, and seasonal temperature swings.
DuraSeal Warm Edge technology is designed to perform under these real-world conditions, helping maintain the integrity of the insulated glass unit for years to come.
4. Better Overall Window Performance
Warm edge spacers help improve thermal efficiency, reduce condensation potential, and contribute to better overall window performance and homeowner comfort.
Why This Matters
Once the seal of an insulated glass unit fails, moisture enters the airspace between the panes. The result is the cloudy or fogged appearance every homeowner dreads.
Because the insulated glass unit cannot be repaired, replacement becomes the only solution.
That’s why the spacer system you choose today can have a major impact on how your windows perform years from now.
The Bottom Line
The spacer may be one of the smallest components of a window, but it plays one of the biggest roles in long-term performance.
Traditional metal spacers conduct heat and place greater stress on the insulated glass seal. Warm edge spacer technology helps reduce heat transfer, improve energy performance, minimize condensation, and protect the integrity of the insulated glass unit.
At Windowcrafters, we believe the details matter. That’s why every window we manufacture includes DuraSeal Warm Edge Spacers as our standard—not an expensive upgrade.
