With Stiffer Requirements on the Way, Prices Are Set to Go Up

By Drew Vass

While the number of new homebuyers looking for the Energy Star label on doors and windows is unknown, there’s no debating that this familiar brand can add a level of assurance about energy efficiency. With recent versions leaning on a climate-zone-based formula for performance criteria (since January 2015), builders can also lean on the label as a straightforward method for selecting the right products for their regions. But the price for those assurances is also set to go up, as the cost for Energy Star-rated doors and windows rises with the latest revisions to the program. Compared to the existing program (Version 6.0), officials for the Environmental Protection Agency (EPA) say it will cost on average $36 more per window to meet the latest proposed criteria (Version 7.0). Some experts say that’s an understatement.

In July 2021, EPA unveiled the first draft of Energy Star Windows, Doors and Skylights Version 7.0, which included significant changes. Performance requirements for entry doors were minimal to none, but the changes for windows and sliding glass doors is a much different story, especially in the Northern climate zone, which encompasses around half of the nation.

If Version 7.0 is enacted as drafted, windows in the Northern zone will need to be nearly 20% more effective at retaining heat. At the same time, they’ll be required to allow a certain amount of sunlight into the building, to avoid being “overly dark,” EPA officials say. They’re worried that too much tint might deter some homeowners from selecting Energy Starrated windows.

In the end, manufacturers say there are numerous ways to meet the newly-proposed criteria. All come at a cost.

Why the Price Hikes?

Stricter energy requirements increase the cost for windows because manufacturers must spend time (and money) tweaking, designing and redesigning products to be more energy efficient. In some cases, that might be as simple as upgrading the glass. The most straightforward path to compliance includes replacing double-pane insulating glass with triple-pane glass, but that’s never a shoo in, manufacturers warn, as most double-pane windows aren’t designed to accommodate the added weight and thickness of triple-pane glazing. Other alternatives have found their way to market fitting the form factor of double-pane windows but, even in those cases, manufacturers will be required to change their equipment and processes to accommodate new types of glass.

It’s easy to understand why government agencies are pressing for more efficient windows. First, officials say that far too many windows meet existing Energy Star criteria, watering down the program’s intent to label the most efficient products. Secondly, “We need something a lot better than R-3.3 if we’re going to address climate change,” says Marc LaFrance, U.S. Department of Energy’s Advanced Technology and Energy Policy manager, referring to today’s best windows. Despite decades of performance gains, “Here we are, after all of this, and we’re still looking at R-3,” he adds. When it comes to wasted energy, “Windows represent only 8% of the service area of a home, but 45% of the thermal loss,” LaFrance says. “So, if you care about climate change and about saving energy, then you have to look at windows.”

The government has already footed the costs for research to advance better products, LaFrance and others suggest, but the final costs for deployment lie with manufacturers.

Skinny What?

As a result of rapid changes, expect to see new terminologies emerge among windows—including significant departures from standard double- and triple-pane glass. Through a relationship with Lawrence Berkeley National Laboratory, the DOE has placed significant stock into a product known as “thin-triple.” You might also see this type of glass referred to as “skinny triples” or “thin glass triples,” as the industry hasn’t arrived at a consensus in nomenclature yet.

Thin triple glass is like standard triple-pane, in that it contains three layers of glass (called “lites”) separated by air spaces. In this case, however, the middle lite is made of the same thin glass that’s used in flat panel televisions. Also, while standard triple-pane glass includes two spacers (the metal or foam piece around the perimeter of the glass, in between lites) in some cases thin triples use one slotted spacer that holds the middle layer of thin glass in place. In standard triple-pane glass, the two air spaces created by three layers of glass are sealed one from another and filled with gas. In thin triples, there’s just one air space, with the thin layer of glass more or less suspended in the middle.

When it comes to thin triple, the bottom line for builders is: the product provides higher levels of performance in a package that’s similar to double-pane, so your crews won’t moan about the added size and weight. But the price is thicker. Some experts estimate that thin triple glass adds as little as $2-$3 per square foot, compared to standard double-pane. But the added costs come in via the changes that window manufacturers must make in order to produce new types of insulating glass. Investments into new materials, processes and equipment will inevitably make their way into the cost for windows.

To date, several manufacturers have begun to offer the option for thin-triple glass in their windows, but more are slated to follow.

A Full Menu to Follow

In the meantime, other glass technologies have emerged offering performance as good as or better than triple-pane or thin triple, but exactly when they’ll go mainstream is not yet known. Vacuum insulating glass (VIG), for instance, has made its way into numerous sectors but remains a niche product for residential. VIG mimics the same technologies patented by Thermos years ago, to keep your lunch vittles warm. In windows, the technology includes two lites of glass separated by a thin void. In standard double- and triple-pane windows, you might call that an “air space,” but in VIG there’s little to no air at all—ideally none. And while standard, double-pane IG holds two lites of glass together using spacers, VIG does just the opposite, by relying on tiny spacers spread out over the glass surfaces to hold them apart so the air can be vacuumed out, leaving a void. With no air for energy to pass through, that void prevents heat loss. The result is performance as good as R-14.

At as little as 6-mm thick for the entire unit, VIG is a far cry from triple-pane in weight and thickness— even thin enough to replace single-pane in historic windows. But the price tag is anything but thin. The costs for VIG have been estimated to be as much as an additional $20-$25 per square foot over standard double-pane. There are other issues to overcome as well. For instance, at 6-mm thick overall, VIG is considerably more fragile than other types of insulating glass. For this reason, some manufacturers have begun to toy with combining VIG with additional lites of glass, for a sort of hybrid combination. Whether or not those options will make their way to the residential market is yet to be seen.

Even with new requirements and all of the latest glass gadgets, you shouldn’t expect to see double-pane insulating glass disappear from the market. In some regions, with the right gas fills and coatings, double-pane glass is more than enough to meet impending standards. It’s also possible that with new requirements, some door and window manufacturers could forego the Energy Star label, but experts agree that’s unlikely. If even one manufacturer places the Energy Star logo on its products and marketing collateral, others are forced to follow. For this reason, expect that most builder-grade windows will continue to bear the price increases that follow.

So far as when you should expect to see prices go up, if things go as planned, a final draft for Energy Star 7.0 will arrive in the first quarter of 2022, after which a final specification will be published in the first or second quarter. The effective date of any new requirements is yet to be determined but could arrive as soon as early 2023. That’s when you’ll need to check with your supplier and up your job estimates.

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