How Next-Gen IG Is Made
by Drew Vass
From thin-glass quads and aerogel IGUs to light-diffusing glass, new forms are stretching the limits of performance and purpose among doors and windows.
For decades now, there have been numerous iterations of insulating glass (IG), but most follow a straightforward formula: two to three lites of float glass, combined with one of several different types of spacer, desiccant, gas fillings and solar coatings. In recent months, however, things have become a bit more complicated. New types have emerged—each vastly different than anything offered in the past.
Thin-triple IG units (IGUs) with an inner lite of thin glass reached the market, calling for new spacer designs, new manufacturing techniques and machinery. No sooner did “thin-triples” come to fruition than Alpen High Performance Products debuted an entirely new construct: thin-quads. The design includes two inner lites of thin glass and three internal cavities.
Another material that’s lingered on the outskirts of the industry also made its debut in IG: a new aerogel from AeroShield Materials. AeroShield’s new aerogel promises to deliver triple-pane performance from a double-pane profile. But thermal benefits aren’t the only thing that’s clear about AeroShield’s new material. Despite its past, the new formula is more transparent than glass, the company reports.
Meanwhile, with its new IG, Advanced Glazings Ltd. of Nova Scotia, Canada, isn’t as concerned with transparency. Instead, the company uses a honeycomb-like insulating core and non-woven fibrous layers to produce glass that scatters and distributes incoming light, turning everyday windows into an effective light source.
Together, these new types of IG stretch the limits of fenestration. But how are they made?
Thin-Glass Quads
In 2024, Alpen redefined thin-glass IGUs, upending industry nomenclature with its thin-glass quads. Since then, the company has offered them to other door and window manufacturers.
AlpenGlass brand IGUs incorporate borosilicate thin glass ranging from 0.5- to 1.1-mm in thickness. According to the company, quad-pane, 1-inch IGUs with two lites of thin glass produce R-15 thermal performance. When compared to double-pane IGUs, the additional weight and thickness is “negligible,” officials suggest.
According to James Satterwhite, vice president and general manager of AlpenGlass, the concept of thin-glass IGUs has been validated through years of development and real-world performance. “I think there’s almost 3 million square feet of this in the market already,” Satterwhite says.
Building a thin-glass quad isn’t as simple as adding two extra lites of thin glass to a traditional IGU, though. The thin, inner lites in thin-glass quads are housed between continuous spacer systems, forming three distinct insulating cavities. Central to Alpen’s process is the use of a thermoplastic spacer (TPS), which forms a continuous, chemically bonded perimeter around each IGU.
There are other ways of constructing thin-glass IGUs—including spacers that are slotted to hold the thin inner lites—but TPS simplifies construction, says Satterwhite.
“[With TPS] instead of a spacer, a primary seal, and a secondary seal, you just have the spacer and the secondary seal,” he says.
The TPS in thin-triples and quads is cross-linked and bonds directly to the glass, as well as the two-part silicone that runs around the perimeter.
TPS also provides greater flexibility in gas-fill configurations, Satterwhite says. That allows the company to develop and fine-tune configurations. Multiple chambers can be either isolated or pressure-equalized, depending on design goals.
“There’s a real dynamic recipe balancing the widths of the spaces with the directionality of low-E coatings, and gas fills like Argon or Krypton,” he says.
Alpen seals its IGUs in an Argon-flooded chamber, ensuring each unit is fully purged before sealing. For units requiring Krypton, the process becomes more intricate, involving extraction and backfilling through dedicated ports, but the process is performed without disturbing perimeter seals.
Specialized Lines
The complexity of thin-glass quads requires specialized manufacturing equipment—machinery that’s flexible enough to produce different configurations back-to-back.
“From a big picture perspective, the manufacturing technology is housed in very similar chassis,” says Alpen CEO Andrew Zech. “Your cutting bridge looks the same. Your lift equipment looks the same. The line looks the same, but the difference is in 1,000 small details.”
Zech says this is especially true when it comes to cutting thin glass, which is more complicated.
“The precision of the cut that you need for thin-glass units is very precise,” he explains. “We have cutting equipment that is the first of its kind in North America. It can cut anywhere from 0.5-millimeter thin glass all the way up to 10 millimeter on the same machine with the same blade, all while achieving excellent edge strength. That edge strength is everything.”
Vertical lines include additional stages for handling different glass types and configurations.
“You’re washing two different kinds of glass—soda lime for the outer lites and borosilicate for the inner ones,” Satterwhite explains. Each requires different wash stations and inspections on the same line, he says.
Once cleaned, each pane passes through an optical analysis station to ensure the quality of low-E coatings. Thin-glass lites then are introduced via specialized pick-and-place systems and indexed slightly inward to avoid perimeter stress, helping to protect edges.
But thin glass isn’t as fragile as you might expect. “It’s actually very tough,” Satterwhite says. “You can take a large sheet and wave it like a piece of lasagna.” Part of the material’s strength comes from its flexibility, he suggests.
With production machinery available and several thin-glass providers on tap, the bigger challenges for thin-triples and thin-glass quads might be on the market side of the equation.
The challenge is scaling the product and making it economically viable, Satterwhite says, which means refining the manufacturing process to deliver high-quality units at high volume and low cost.
IG With Aerogel
For decades, aerogel has been known as one of the world’s best insulators. It is used in everything from space suits to pipelines. But one thing kept it out of windows: opacity. Now, thanks to a material science accident turned innovation, AeroShield has achieved a material that’s not only transparent, but, according to company officials, clearer than glass.
While aerogel has always been hazy, or translucent, AeroShield’s new formula is clearer than glass, officials say.
The breakthrough came during an MIT solar research project, when AeroShield CEO and co-founder Elise Strobach, Ph.D., and her team accidentally added too much catalyst to a batch of aerogel. What emerged was a denser, crystal-clear material that retained the same nanostructure critical for thermal insulation.
The pores in traditional aerogels are about 20 nanometers wide. “AeroShield’s material has just 3 to 6 nanometer pores,” Strobach says. That reduces light scattering and gives it clarity, she says.
The result is a solid, highly insulating layer that allows more light to pass through than standard float glass—all without any of the tinting or haze associated with standard aerogel. The MIT spinout has teamed with ODL Inc. to bring its breakthrough material to market—first in doors. So far as how aerogel IG is made, it might be simpler than you think.
The process of making AeroShield’s material starts with mixing a specific blend of chemicals that gel into a nanostructured matrix. That matrix is then dried using a special piece of equipment called a critical point dryer.
You can’t just air-dry aerogel, says Aaron Baskerville-Bridges, co-founder and vice president of operations for AeroShield, else it collapses like a drying sponge. Instead, a critical point dryer removes moisture while preserving the structure that gives it both clarity and insulating power, he says.
AeroShield’s product is applied to IG by forming it into sheets and bonding it directly to glass, functioning like a large-format coating. Once sealed inside an IGU—typically on surface three, opposite a low-E coating—aerogel becomes a passive insulator.
You cut it to size, apply to glass, then place a spacer around it and seal the unit—just like any other IG, says Baskerville-Bridges.
According to AeroShield, the material effectively doubles the insulation value of traditional gas fills, like Argon or Krypton, without increasing IGU thickness.
This is ideal for applications where you can’t add bulk—like entry doors and patio doors, Baskerville-Bridges says.
AeroShield’s pilot manufacturing facility in Waltham, Massachusetts, is already producing full-size sheets. The team is focused on scaling output using semi-continuous production techniques that mirror the autoclave or lamination processes common in glass fabrication.
While the first use case is within traditional IGUs, AeroShield’s aerogel also pairs well with smart technologies, like electrochromic coatings or photovoltaic glass, Baskerville-Bridges says. The material is also being explored for retrofit applications, including as secondary glazing, to provide aerogel-glass laminates that could install over existing windows.
By 2026, AeroShield’s aerogel-insulating glass is expected to hit the market through ODL’s entry and patio door offerings. Longer-term, the company envisions licensing the technology, producing aerogel-coated glass for IGU manufacturers.
Light-Diffusing IG
For decades now, windows in residential buildings have required a compromise between access to light and control over thermal heat gain. Coatings and films can help to control that dilemma, but Advanced Glazings’ new, light-diffusing IG aims to turn doors and windows into high-quality light sources. Rather than controlling sunlight with coatings or films, Solera IGUs use light-diffusing “veils” to distribute and evenly project soft, ambient daylighting deep into interior spaces. The company can fine-tune diffusion, visual light transmittance and solar gain by utilizing various combinations of its materials. Like other forms of IG, the product also maintains thermal performance through the use of a transparent, insulating core that can even be combined with aerogel.
The idea is to harness as much natural light as possible without the typical drawbacks. Similar to other forms of IG, Solera IGUs feature a “sandwich” style construction, says Doug Milburn, founder and chair of Advanced Glazings.
The product is constructed like any other IG, but with special, non-woven fibrous layers bonded to the lites of glass, he says. The fibrous materials are designed specially for color stability, so they won’t degrade or change over time. In between lites, a honeycomb insulator is used to reach R-5 performance, to which aerogel can be added to reach as high as R-25, the company reports.
One company that’s partnered with Advanced Glazings includes Wintech Inc., a door and window manufacturer in Monett, Missouri, including on its OzarkView line of windows. Solera IG incorporates into windows the same as other types, says Adam Verstraete, WinTech’s division manager.
Meanwhile, standard IG produces “bright spots, dark spots and heavily shaded spots, because the sun only lights where it’s hitting,” Verstraete says. With Solera, you get “light spread throughout the room and nice, even ambient light,” he adds.
As codes tighten, light-diffusing IG, thin-glass quads and IGs with aerogel may offer a pathway to adding more glass to new homes. In the meantime, they add a bit of excitement to an industry that, until recently, has seen incremental change.
What Is Aerogel?
Aerogel is a lightweight material composed of more than 95% air, forming one of the best thermal insulators known to science. Traditionally, aerogels have been cloudy and brittle, but AeroShield’s version is transparent, flexible and engineered specifically for use in insulating glass.
Key Benefits:
- Twice the insulating value of inert gas fills;
- Clearer than glass;
- Works in a standard double-pane IGU;
- Enables thinner, lighter products; and
- Compatible with retrofit and smart technologies.
Drew Vass is the executive editor of [DWM] magazine.
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