With the Arrival of Energy Star 7, Will VIG and Thin-Triple Finally Have Their Day?

[Spoiler Alert: Probably Not]

By Drew Vass

After more than half a century of relying on double-pane insulating glass (IG) as a go-to product, you might expect U.S.-based door and window manufacturers to be ready for a new hero. But so far, no glass technologies have shown up to save the day.

After decades of development, vacuum insulating glass (VIG) and thin-triple glass (sometimes referred to as “skinny triples”) await their time in the mainstream. And with Energy Star 7.0 (ES7) set to take effect in October 2023, you might expect one or both to find their way in the weeks ahead. For now, though, it seems that manufacturers will be sticking with double-pane glass.

In the development of ES7, officials for the Environmental Protection Agency (EPA) welcomed this
outcome by backing off of an originally proposed U-factor requirement of 0.24 for the North-Central zone, acknowledging that those measurements would be “a tough U-factor to get to with two panes of glass.”

While triple-pane glazing is the standard in Europe, U.S.-based manufacturers have so far avoided
redesigning most mainstream products to accommodate thicker and heavier glass, mostly by adding additional low-E-coatings. Meanwhile, regarding VIG and thin-triple, “Personally, I would have thought they both would have been more mainstream by now,” says Frank Anderson, president of Sun Windows Inc., in Owensboro, Ky.

Instead, both remain held back by key issues—some of which they’ve faced for years.

After reaching out to more than 60 door and window companies, only three tell [DWM] they’re
currently offering or are in the process of deploying thin-triple IGUs: Alpen High Performance Products, Andersen Corp. and PGT Innovations. None say they’re currently using or planning to offer VIG, except in rare instances, and only a handful of companies say they are evaluating one or the other for deployment. With ES7 taking effect in mere weeks, it’s clear by now that most door and window manufacturers won’t be relying on either to meet the new criteria.

At the same time, “We talked to several [door and window manufacturers] and they were still deciding a few months ago what to do,” says Tim McGlinchy, executive vice president of engineering and R&D for GED Integrated Solutions. “And I’m like, ‘Well, the deadline is in October.’”

It appears that the industry might be locked in a wait-and-see status, McGlinchy and others suggest— waiting to see how the market responds to the higher costs of ES7-rated products. “I think some are taking that approach,” he says. “Like, let’s see how popular it is.”

That’s not to say that door and window manufacturers are asleep at the wheel. Any delayed reaction to ES7 could be as much about deliberation than procrastination, says Michael Rapp, president of sales for PDS IG Equipment. “I think this is something that window manufacturers aren’t taking lightly,” Rapp says. “They’re putting a lot of work into ensuring that the decisions they make are the correct ones going forward.” There is also a possibility they’re focused on competing and “don’t want to show their cards too soon,” he says.

Waiting for a Sign

As manufacturers weigh the costs of investing in VIG or thin-triple, many are also unsure of whether or not consumers will pay extra for the Energy Star label after ES7 takes effect.

“In our market, we anticipate customers won’t pay for the upgrades to ES7, so we plan to offer a lower-cost alternative as well,” says Bill Hoberg, president of Glass-Rite, a door and window manufacturer that’s based in Albuquerque, N.M.

For now, it appears that some will stick with variations of double-pane, low-E-coated glass, while
keeping standard triple-pane as an option should the market embrace added costs for the Energy Star label.

Why has ES7 failed to stimulate VIG and thin-triple? Both are held back by higher costs, McGlinchy
says. VIG is also limited by a lack of available sizes and the need for new frame designs to accommodate its nominal thickness. At around 8 mm, product engineers must figure out what to do with all of the added space VIG leaves behind, when compared to ¾-inch, double-pane glass.

A lack of available sizes for VIG units also goes against the industry’s modus operandi, says Bill Sifflard, chief marketing officer for Quaker Windows & Doors. “I think the big challenge with VIG, from what I have been told, is that you are limited to specific sized units and even though they are common within our industry, so much is centered around custom sizes,” Sifflard says.

According to McGlinchy, these problems span as far back as the mid-1990s but have yet to be addressed.

Among the major gripes for VIG, manufacturers also maintain that availability remains limited. The vast majority of VIG units are made in China (90% some experts estimate), which, in addition to limiting availability, also adds to their cost. “So, a 25% tariff, 5% customs duty, shipping, transportation, insurance—all of that to get this product here. There’s a premium,” says [DWM] columnist Dave Cooper, president of Fenestration Consulting Services LLC.

As a result, “Product is still extremely expensive. So, you know, the cost justification for the performance and thermal value, relative to the cost for someone to own it, is just miles apart,” McGlinchy says.

For these and other reasons, “I don’t believe vacuum units will be viable for some time, and I would
be concerned about warranty issues, high costs and smaller size requirements,” Hoberg says.

Bob Keller, senior vice president of product innovation and technology for PGT Innovations, concurs.

“At this point, the technology is still several years away from reaching commercial-level scale in the residential market,” Keller says.

Who’s That in the Mirror?

Unlike VIG, which is well defined at this point, thin-triple glass faces another issue: an identity crisis. While the material has been in development for decades, a number of configuration options and methods for construction obscure what the term “thin triples” means or includes. In some cases, nomenclature comes down to marketing.

“What’s a thin triple? And is a thin-triple the same as a thin-glass-triple?” Rapp asks. Others use the term “skinny triples,” alluding to the product’s overall thickness as a key marketing term
(which is in line with double-pane glass).

“There are a lot of discussions going on, but no clear line in the sand,” Rapp says. What is clear is that folks are trying to find ways to use thinner glass, he says. Others have gone their own way with marketing and branding. PGT Innovations, for instance, is gearing up to offer triple-pane units with a special, laminated thin glass the company codeveloped with Corning Inc., dubbed Diamond Glass. The company plans to use the product in its own doors and windows, while marketing it to other manufacturers as well.

But thin-triples face more than just an identity problem. Like VIG, the product continues to battle
issues of affordability as well. Not only is thin glass more expensive and harder to obtain than regular glass, but the cost of Krypton gas, one of the product’s essential elements, has increased significantly in recent years.

“Five years ago, Krypton was much less expensive than it is today,” Cooper says. “In fact, it dipped about five years ago. Now it’s back to where it was or even more. There just isn’t much of a supply around the world and apparently quite a bit of it comes from Russia. So that’s a problem.”

Differences In Equipment

When glass is available, both thin-triple and VIG also require specialized—and in some cases, extremely expensive—equipment to produce. Meanwhile, as door and window manufacturers hold out to see how the market responds to ES7, some equipment manufacturers are taking the same stance. Among the 13 machinery manufacturers polled for this article, just two said their equipment could be used for some aspect of VIG production, though, none claimed to have complete manufacturing set-ups. Only one said it had a complete system designed to produce thin-triple IGUs. When asked if any of their existing equipment could be used or adapted for use with thin glass, a number of manufacturers replied with, “Maybe.”

In the case of VIG, supportive pillars must be added between two layers of glass to hold them apart. In some cases, they’re added via a method that resembles printing. In other cases, they’re mechanically set in place. While VIG doesn’t employ a traditional spacer, it uses an edge seal to create and preserve the vacuum—all of which requires an entirely different set of equipment, when compared to standard IG.

When it comes to thin-triples, cutting, handling and cleaning all pose challenges, machinery experts say. For lifting and moving, thin glass is akin to picking up a piece of paper, bending under its own weight.

Questions also remain around whether thin glass can be tempered by traditional means and what the costs of any alternative methods might be. Vertical processes that include additional rollers and horizontal systems utilizing airflow to manipulate glass both can be used, but, “The question is always how big can you go and how thin can you go in these furnaces?” Cooper says. “There could be some real limitations there.”

In the end, one thing is clear: There’s no one-size-fits-all method for assembling various thin-triples. PDS IG Equipment offers machinery to make thin-triple units with a single, flexible stainless-steel spacer. But the same system cannot be applied to other versions of thin-triple glass. Others produce the product by using a slotted, foam-based spacer, or two traditional spacers, like standard triple pane. Each variation carries a different protocol for manufacturing.

In the case of PDS, the company’s equipment robotically handles thin glass to add the flexible stainless-steel spacer. The spacer is then adhered to two outer lites of glass the same way you would construct a standard, double-pane unit, with the inner lite of thin glass already in place.

“Essentially you have a dual-pane unit with a third lite of glass that’s sitting in the middle, breaking up the two cavities,” Rapp says.

Waiting for the Cards to Fall

In the end, some equipment manufacturers are waiting to see which versions of the product are commercially viable before setting out to design new systems.

“We were approached several times to develop equipment, but the reason we didn’t hop in is because if the economics don’t work and the market doesn’t want it, I can’t see automating something expensive that nobody wants, right?” McGlinchy says. “We were invited to the table many times and I just couldn’t see the main trend. As equipment manufacturers, we
want to sell a lot of equipment, right? I don’t want to build one plant and be done. We just can’t make money that way.”

It’s entirely possible that consortiums will form, as companies look to band together to invest in manufacturing, Cooper says. But equipment companies may also have to step up by designing machinery and producing small amounts of product to bait the industry into acceptance, he suggests.

In the interim, some companies are gearing up for production of regular triple-pane IGUs as a backup, for cases where double-pane IG won’t hit the mark for ES7.

“These companies have been paying attention and, knowing what’s coming, they’ve started to increase the depth of their framing pockets,” Cooper says. “So, they’ve already started making the decision that, if we have to make framing modifications, we’re going wider—we’re going to a [standard] triple.”

McGlinchy concurs that standard triple-pane glazing will likely be a stand-in for cases where customers want Energy Star-rated products and low-E-coated double-pane glass can’t meet the mark for performance requirements. “I think it’s going to be a stopgap,” he says. “You know, it used to be you had to be Energy Star [rated]. But I think people have reached their limits. So now I think they’re going to say, ‘Yeah, we offer that. But you’re going to have to get triple-pane
glazing.’ And a lot of people aren’t going to want to pay for that. They’re going to be made-to-order, not necessarily stocked products.”

In this way, it will be consumers who decide whether manufacturers develop and offer Energy Star-rated products as off-the-shelf items or not. If they’re willing to pay, manufacturers can then decide whether to pursue thin-triples, VIG or regular triple-pane glass where necessary.

“This will always come back to the carrot and the stick,” Cooper says. “The carrot being some sort of tax incentive or rebate program.”

Drew Vass is the executive editor for Door and Window Market [DWM] magazine.

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