What Is a Warm Edge Spacer Bar?

How do warm edge spacer bars work?

Warm edge spacer bars work by replacing highly conductive materials — like aluminium — with low-conductivity alternatives such as structural foam, thermoplastic or composite materials. Positioned at the perimeter of the sealed unit, they interrupt the thermal bridge that would otherwise allow heat to transfer from the warm inner pane to the cold outer pane.

This keeps the window edge warmer, reduces condensation on the inner glass surface, and maintains consistent thermal performance across the full glazed area. Edgetech’s Super Spacer® achieves a thermal conductivity (λ) of just 0.19 W/mK — significantly lower than aluminium at around 160 W/mK.

What are the key performance benefits of warm edge spacer bars?

Switching to warm edge spacer bars delivers measurable improvements across four areas:

Improved U-values — Warm edge spacers reduce the edge-of-glass U-value, contributing to the overall window U-value. For a standard double glazed unit, this can mean the difference between a C-rated and a B-rated window under UK energy labelling.

Condensation resistance — By keeping the inner glass edge above the dew point, warm edge spacer bars significantly reduce condensation on the window’s interior surface — protecting frames, seals and sills from moisture damage.

Lower heating bills — Reduced heat loss at the window perimeter translates directly to lower energy consumption. Across a full property retrofit, the cumulative saving is substantial.

Extended window lifespan — Less thermal stress and reduced moisture ingress means the sealed unit lasts longer, protecting your investment and reducing maintenance costs.

What applications are warm edge spacer bars used in?

Warm edge spacer bars are good for many types of buildings. In homes, Super Spacer® can make your space more comfortable and save energy. It offers great thermal insulation. This helps lower heating costs and reduce carbon emissions in both double and triple glazing systems.

For commercial buildings, which often use a lot of glass, products like TriSeal™ and T-Spacer™ meet strict performance standards. They help reduce heat flow between the inside and outside. Their strength and energy-saving qualities make them ideal for large projects, including office buildings and tall skyscrapers.

These spacer bars perform exceptionally well in extreme climates, adapting to both hot and cold conditions while maintaining their thermal properties and structural integrity.

What is the difference between flexible and rigid warm edge spacer bars?

Flexible warm edge spacers, like Super Spacer®, are made from structural foam and offer superior flexibility and ease of application. Rigid warm edge spacers, like TriPlas®, provide traditional aesthetics while maintaining thermal performance. Both types offer significant advantages over traditional aluminium spacer bars.

Why is a warm edge spacer bar better than traditional metal spacer bars?

The kind of spacer bar you choose can make a big difference in how well windows work when it comes to energy efficiency. Windows that perform better stay efficient for a longer time. Warm edge spacer bars are much better than older materials like aluminium, a highly conductive metal, as they have better thermal properties. They conduct heat less and provide superior gas retention within sealed units.

Edgetech: The home of warm edge spacer technology

As pioneers in warm edge technology, Edgetech leads the industry with innovative modern warm edge spacer bars. Our flagship Super Spacer® – the world’s first flexible foam spacer bar – continues to set the standard for thermal efficiency.

TriSeal™ is a special version of Super Spacer used in commercial buildings. Many large projects around the world use it because of its unique ‘triple-seal’ design. Our T-Spacer™ is a version of TriSeal™ designed for machines that place spacers automatically.

TriPlas® is our rigid warm edge spacer bar and has been designed using glass reinforced thermoplastic spacer technology for increased stability and strength over other rigid warm edge spacer bars.