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Warm Edge Spacer Bar Technology

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The UK's number one choice of warm edge technology

Warm Edge Technology

At Edgetech, we create cost-effective, high-performance warm edge spacer systems that have changed the face of glass unit manufacturing.

Warm Edge technology has radically changed the window market by significantly improving thermal performance compared to highly conductive aluminium spacer bars to reduce thermal conductivity, lower heat loss through windows and improve the energy efficiency of insulating glass units.

Our highly insulating warm edge spacer bars help insulating glass unit manufacturers maximise the thermal performance of their finished window products and help homeowners save money on their energy bills.

What is an Insulating Glass Unit?

Often known as double or triple glazing, insulating glass units typically consist of two or more panes of glass that are separated by a spacer material and sealed together.

The insulating space between the panes of glass is filled with either air or a noble gas such as Argon or Nitrogen to allow the insulating glass unit to reduce heat transfer and help improve the energy efficiency of the building they are installed in.

Insulating glass units have been around a lot longer than we think and so has the concept of warm edge spacers. The first insulating glass unit was patented in 1865 by Thomas D. Stetson and warm edge technology was a natural part of the early invention, using metal to space the panes apart was never intended but aluminium spacers were used for many years.

In fact, it took over a century for spacer bar to catch up with the basic principle of the invention. Today, warm edge spacers are widely used in place of aluminium spacers.

How do Warm Edge Spacers Compare to Aluminium Spacers?

The material that is used to manufacture the insulating glass unit spacer plays an important role in determining how much heat and cold is able to pass through the glass panes and therefore is a major factor in the energy efficiency of an insulating glass unit.

Traditionally, aluminium spacers were used because of the structural properties of the material. However, aluminium is an excellent conductor for heat which meant aluminium spacers actually helped heat from inside the building escape to the outside. Aside from heat loss, the cold edge created by aluminium spacers also made the insulating glass units more prone to condensation.

Warm edge spacers are made from materials with low conductivity, which significantly improve the thermal performance of insulating glass units. This not only helps to prevent heat loss and improve the energy efficiency of the unit, but it also helps to remove the cold edge to reduce condensation.

History of Edgetech’s Spacer Bars

The 1970s
First all-in-one single seal spacer launched


The 1980s
Super Spacer launched to market


The 2010s
TruPlas thermoplastic spacer launched

Super Spacer - Clean Lines for Triple Glazing

Our Range of Warm Edge Spacer Systems

Approximately one-third of all insulating glass units in the UK are made with Edgetech’s warm edge spacer systems. We offer a wide range of products for the glazing industry.

Flexible all-in-one Spacers

Our flexible all-in-one spacers include the Duralite warm edge spacer, which is suitable for use with double and triple pane insulating glass units. It is a warm edge spacer system that is applied in a single step using heat and minimal compression to provide superior durability and thermal performance.

Flexible Foam Spacers

Our broad range of flexible Super Spacers use foam spacer technology for superior perimeter insulation for sealed glazing units and are designed to help prevent heat loss, improve production efficiency, reduce costs, improve energy efficiency and eliminate mould causing condensation.

Rigid Plastic Spacers

Using glass reinforced thermoplastic spacer technology, TruPlas is designed for increased stability and strength over other rigid warm edge spacer bars and its ridged surface provides a traditional appearance.

Warm Edge Spacers for Commercial Projects

Super Spacer TriSeal is a flexible spacer that uses foam spacer technology to help it meet the toughest commercial glazing demands. TriSeal has a unique triple-seal design that incorporates an inner PIB seal for compatibility with structural secondary sealants.

super spacer cross-section

Why Choose Warm Edge Spacer Technology?

  • Drastically improve the energy efficiency of IGUs
  • Maximise thermal performance of finished window products
  • Reduce the risk of condensation
  • Reduce home energy consumption

Spacer Bar FAQs

Edgetech’s spacer bar expertise has considerably simplified the process of manufacturing sealed units ever since we launched the world’s first flexible foam spacer bar in 1989. As pioneers in warm edge technology, we thought we’d take the opportunity to answer some prominent frequently asked questions.

What are spacer bars for?

Insulated glass sealed units (IGUs), also known as double glazed window units, are constructed with two panes of glass that are kept apart by a spacer bar (or pane spacer) that sits around the inside edge of the glass. Previously made from aluminium, Edgetech proactively developed the first flexible spacer bar made from structural foam, setting itself apart from competitor brands via its time-saving pre-desiccated material, and no need for PIB primary seal application due to pre-applied side adhesive.

Aluminium spacer bar – how has the material evolved?

The traditional aluminium box spacer design offered the glazing industry a lightweight, durable, relatively low cost and plentiful supply for over 40 years. However, aluminium’s main downfall was its rigid, highly conductive, energy wasting qualities. Foam spacer bar technology at Edgetech has outstanding structural integrity, including 100% memory features. Coping with different rates of glass expansion and frame materials put under varying temperatures and tensions, unlike classically inefficient aluminium spacer bars, foam spacer bars always return to their original shape and dimensions and maintain a sound edge seal under virtually any high-pressure glazing situation. 94% of energy loss happens at the edge of the window. So, comparing thermally inefficient aluminium vs flexible Super Spacer® and TruPlas™ rigid spacers, warm edge spacer bar technology is up to 950% less conductive than aluminium.

Is warm edge a new concept?

Surprisingly, warm edge spacer bar technology has been around since 1865! Can you believe that the first patented IGU, created by Thomas D. Stetson, consisted of cellular wood strips or rope and thatch or tar?! The evolution of the insulated glass unit has gone from strength to strength over the last 50 years;

How do warm edge spacer bars contribute to saving costs?

Super Spacer® & TruPlas™ products effectively prevent heat from escaping from the window unit, which considerably lowers heating bills. Super Spacer products are so efficient that they been certified by the Passive House Institute (PHI) or ‘Passivhaus’ in Germany for the most extreme climates and performance requirements. The absence of a cold edge intensely improves the comfort and enjoyment of any building that warm edge spacer bars are applied to, as well as creating an effective barrier against the likes of condensation and mould – which can become a costly issue if left untreated. Considering around 1 in 4 UK homes have an issue with condensation or damp, alongside 5.4 million people in Britain actively receiving treatment for asthma, spacer bar technology has notable health benefits too. Super Spacer also carries a 40-year performance guarantee; saving property owners more money in the long-run as IGU’s will effectively last longer.

How sustainable are spacer bars?

Sustainability is an incredibly important issue to homeowners and businesses alike. By utilising warm edge spacer bars within residential and commercial structures, sustainability is translated via impressive reduced U-values of up to 0.2W/m²K and noise pollution reductions of up to 2dB. Extreme pressure to the insulated glass unit’s perimeter seal is also ‘dampened’ by Edgetech’s Super Spacer® and TruPlas™ rigid spacer. The foam intelligently flexes with the glass, resulting in lessening pressure and less unit failures and stress cracks. This translates into less waste all round, which helps to reduce carbon footprints further. Plus we are so certain of Super Spacer’s durability, if service conditions are met, glass units that use the product come with an unrivalled 20-year guarantee.

Do spacer bars reduce condensation?

Edgetech’s Super Spacer® and TruPlas™ rigid spacer offer proven performance via a dual seal insulating glass spacer system, alongside a high-performance acrylic adhesive backed by a multi-layer moisture vapour seal. This spacer bar range actively reduces perimeter condensation by up to 70%, compared to traditional aluminium spacer bars.

Where can I find the most efficient, productive and consistent spacer bar?

Edgetech’s Super Spacer® products are easier to apply than any other spacer bar on the market, by utilising either manual equipment to produce 250 units per shift through to a high-speed, fully automated line that can impressively manufacture up to 1,400 insulated glass units in a single 8-hour shift. Making considerable monetary and time savings for IGU manufacturers, it also removes the need to cut it into bar length form as it’s applied continuously in a flexible continual reel. There is no need for a PIB primary seal or desiccant filling either, as the product is pre-desiccated and has an acrylic seal applied already for assembly. Therefore, productivity is heightened even further with a simplified 4-point manufacturing process and just 3 workers required in IGU production, in comparison to the lengthy 9-point manufacturing process and 6 workers required in IGU production that’s typical of conventional, conductive aluminium box spacers.

For IGU manufacturers that want to maintain their existing manufacturing setup but want to improve on the performance of conventional aluminium spacers the TruPlas rigid box warm edge spacer is available in 3 colours and a wide range of widths. It has been designed to make manufacturing easier by offering reduced static, reinforced shoulders to prevent drooping in large IGUs and is less brittle than alternative products.

Edgetech’s spacer bar range  is also helping installers meet the increasing demands of homeowners, who require double glazed products that can offer A-ratings that will truly stand the test of time.

Related to this post: JWC Group Spots the Trends

Can you provide any examples where Edgetech spacer bars have been used?

Let’s explore some buildings that are dedicated to thermal efficiency and carbon neutrality, with the help of Edgetech’s spacer bars.

Super Spacer® soars in Denmark’s eco-friendly Maersk Tower

Super Spacer® soars as part of iconic addition to Dubai skyline

Synseal selects TruPlas™ for Global Glass Wigan

TruPlas™ Goes Global

WET foam spacer bars: small component, big impact

Click here for more information on manufacturing IGUs with Super Spacer® and TruPlas™ rigid spacer. We haven’t been named Spacer Bar Manufacturer of the Year three years for nothing!

  • Sound dampening technology

    Reduces external noise pollution by up to 2dB

  • SuperSpacer reduced condensation

    Reduces condensation by up to 70%

  • Thermally efficient

    Successfully tested from -15° to 125° C

  • SuperSpacer Benefit4

    More than 100 EN1279 Part 2 & Part 3 passes

  • SuperSpacer 40-year performance guarantee

    40-year performance guarantee

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    View our Warm Edge Technology Infographic