Everything IG November/December 2020

July 28th, 2021 by Nathan Hobbs

When Will VIG Catch On? As Soon as Production Comes to America

By Dave Cooper

A question I’m often asked is: When will vacuum insulating glass (VIG) catch on in North America? The answer is that it could be now, but the details are complicated. We can start by breaking the market down into five categories—bearing in mind that use in one can help to propel others. Let’s discuss what drives adoption.

Commercial Glazing

The commercial segment is aware of the advantages in VIG over other types of glazing, including certain code requirements and increased window-to-wall ratios at respectable heat transfer rates. Advantages also include weight savings. As a result, there are several commercial buildings that now incorporate VIG. On the contrary, obstacles include sourcing, size and form factor, as VIG currently is shipped from across the Pacific, making logistics, timing and replacements prime considerations. Another hurdle includes size. Most VIG manufacturers are limited to roughly 7- by 10-foot units, so the trend toward larger glass creates a barrier. Cost is certainly a factor, as well, but to a lesser degree than in other categories.

Retrofit and Residential

For retrofit applications, VIG is a natural fit. Older windows with frames for single-pane glass can be deglazed and the old glass replaced by VIG. This is attractive for use in older historical buildings, especially on such things as university campuses, churches and municipal buildings. For larger buildings, adding a layer of VIG to the building’s existing single pane glass brings enormous thermal benefits, especially if the heating, ventilation and air conditioning (HVAC) system has reached the end of its useful life. Calculating whole building heat loss with an added VIG layer will greatly reduce both capacity and operating costs.

Aside from specialized retrofit applications, implementation among residential windows has been largely non-existent, but that doesn’t mean that major window companies haven’t been evaluating VIG for well over a decade. There are obvious advantages to be gained with R-5 and even R-10 performance. According to the Department of Energy’s 2014 report, “Windows and Building Envelope Research and Development Roadmap for Emerging Technologies,” highly insulating windows are at the top of the list for the category “Highest Priority R&D Areas,” as both new construction and renovations will benefit. Among the major stumbling blocks for wide adoption are added component costs, form factors and the many variants needed. Another includes local availability.

Skylights

Skylights are an interesting category, as it isn’t as widely understood that energy loss is calculated at a 20-degree slope, impacting loss measured due to convection. VIG with (virtually) no gas between glass lites has no convection, greatly benefiting skylights when it comes to U-factor. There is great interest in incorporating VIG into skylights, with European manufacturers pursuing this technology. Again, it comes down to sourcing, availability and cost.

Commercial Refrigeration

Use of VIG for commercial refrigeration is perhaps the easiest application, as many rectangular units of the same size are incorporated into standard doors. For this reason, you may have noticed VIG in your grocery store’s frozen aisle section. Energy savings is a key factor for these superstores and grocery chains, as they understand the cost saving benefits quite well.

Why should companies servicing residential doors and windows be concerned with all of these sectors? Regardless of what drives the need, once a fully functional VIG fabrication plant is operational in the U.S. and the manufactured cost is closer to that of current best in class, standard insulating glass, the technology will become more widely adopted across all sectors – including residential. What will VIG cost in the future? That is a topic for another article.

Dave Cooper is a consultant and president of Fenestration Consulting Services LLC.
dcooper@fenconsultant.com

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