Small but mighty – how spacer bars created the modern window

Chris Alderson reflects on the crucial importance of warm-edge technology to the development of the modern window, and Edgetech’s ever-growing range of advanced spacers.

Spacer bars are tiny, and most people in the world don’t know they exist. But as everyone in the glazing sector knows, they’re a vital part of how modern windows can deliver exceptional thermal and acoustic performance.

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At Edgetech, we’ve been passionate about the power of warm-edge technology for over thirty years.

It might’ve existed long before us – it was invented in Victorian times, when wood or rope was used to separate the panes in the earliest double glazed windows – but we’re proud to have played a major role in bringing it firmly into the mainstream.

When Edgetech was first founded, metal spacers were still the norm – but they came with significant drawbacks.

Metal conducts heat, and that means that windows made with metal spacers very quickly let the warm out, and the cold in. Draughty homes and higher heating bills were the result.

Our modern iteration of warm-edge technology rectified that. By using highly-advanced plastics and foam rubbers rather than metal, warm-edge spacers – like Edgetech’s pioneering Super Spacer® which has been in continual use for over thirty years – were able to offer vastly better performance.

It’s no surprise that, today, warm-edge spacers have become the norm.

Flexible and Rigid

Flexible spacers like Super Spacer are extremely versatile and their flexible design means they can be used to easily create unconventionally-shaped units, freeing up architects to be as bold and ambitious as they like.

It’s Super Spacer® TriSeal™, for example, that’s in the over four-thousand irregularly-shaped IGUs that make up Dubai’s The Opus tower, one of the world’s most striking and complex buildings, and the Qatar National Library.

Its matt material finish means that it blends in with all window colours too, offering homeowners and architects alike seamless aesthetics.

Another key strength of a quality flexible spacer is its memory. In parts of the world where strong winds or fluctuating temperatures are the norm, IGUs are put under a lot of pressure.

Super Spacer’s 100% memory means that no matter how much an IGU expands or contracts under pressure, it will always return to its original position, but is flexible enough to move with the glass which reduces the stress on the glass edge.

This is one of the reasons it’s commonly found in ambitious buildings in the Middle East, where day and night temperatures can drastically vary.

Super Spacer isn’t just suited for grand feats of architecture, however – its exceptional strength, reliability and performance have seen it used in millions of households all over the world.

Fast manufacturing

What’s more, Super Spacer units can be manufactured in under twenty seconds.

Even using our most basic, entry-level manual application tools, we’ve seen some people assemble a unit with it ready for secondary sealing in under 15 seconds.

Upgrade to a fully-automated Super Spacer line, and the efficiency gains drastically increase. A nine-person line applying traditional rigid spacers can produce around 1,200 units every shift.

A high-speed automated Super Spacer line, by contrast, can produce 23.5% more units and requires just 3 to 4 employees to operate.

In total, that equals savings of approximately £180,000 every year.

Widest Range

Our flexible spacer range also includes Duralite® – a durable, single-seal, high-performance product that can be applied in a single step for outstanding thermal performance and cost effective volume manufacturing.

Rigid spacers, like Edgetech’s TruPlas® offer improved thermal performance over metal spacer bars, and companies can switch to them from their metal counterparts easily, using their existing machinery.

TruPlas is made of high-performing glass-reinforced thermoplastic, and has delivered stability and thermal efficiency for homes all around the world.

More advances around the corner

But befitting Edgetech’s long-standing commitment to constant innovation, we’re currently hard at work developing several innovative new spacer bar products.

We’ve just released the latest evolution of our heavy-duty T-Spacer™ product line – T-Spacer™ SG, offering enhanced shape memory, and thermal conductivity of just 0.19W/m²K.

Super Spacer® T-Spacer™ SG is a metal-free, silicone-based warm edge spacer made of structural foam, with an integrated desiccant that’s been specifically designed for the toughest commercial applications.

On demanding commercial projects its extremely durable edge seal guarantees exceptional performance and stability.

What’s more, we’re working on a number of other revolutionary new designs, including additions to our Super Spacer platform and a new rigid spacer too – so watch this space!

2020 has been a challenging year for everyone – but at Edgetech, we’re committed to continuing to push spacer technology forward, and helping glazing products offer the outstanding performance we’ll need to hit net zero carbon by 2050.

For more information please call + 44 (0) 2476 639931 or visit

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