Energy Innovation

With an emphasis on net zero, where does fenestration go from here?
Rich Rinka
August 30, 2018
COLUMN : Decoded, THE TALK... | Codes & Standards

About 50 years ago, there were essentially only two window framing materials to choose from for residential buildings: wood and mill-finish aluminum, typically with single-pane glass. My childhood home near Milwaukee was like a lot of other homes that were built following World War II. Despite my father’s best attempts to add “storm windows” (read: putty glazed, ¼-inch glass in a wooden frame), ice formed on the interior surface of the glass during winter. It was accepted as the nature of things; heat loss was not a big consideration.

However, the first energy crisis of the 1970s and increasing utility costs focused attention on the energy efficiency aspects of windows. Consequently, within the last 30 years, we have seen the advent of low-emissivity coatings, low-conductance gas fills, “warm-edge” spacers and insulating frame systems based on a wide variety of polymerics, as well as wood and aluminum. 

The growth of the scope and depth of the underlying AAMA standards reflects this advancement. Originally just for aluminum, vinyl was added in 1986, and wood was included in 1997 with the original ancestor of today’s NAFS. The scope of the standards grew from covering 10 product types in 1968 to 45 today.

There are still a number of energy efficiency improvements available. Some of the emerging technologies are already nearing the practical stage, such as aerogel insulation and new configurations of triple or even quadruple glazing, such as “thin lightweight triple” glazing, capable of driving U-factors down to 0.10.

What’s next

Recently, Lawrence Berkeley National Laboratory alumnus Stephen Selkowitz challenged AAMA national conference audience members to envision an even more wide-ranging future for fenestration. In terms of energy, the vision is for a “net zero envelope,” a concept that borrows from the California initiative to achieve Zero Net Energy—new residential buildings that produce as much as they use—by 2020. 

A significant challenge to be sure, but one that means new business opportunities, greater occupant benefits and increased real estate value. The latest in the ZNE quest is that all new California homes now must incorporate solar, along with energy storage devices to level out supply to coincide with actual demand. Building Integrated Photovoltaics—which are, in essence, transparent solar cells—have the potential to turn the building envelope into a power source. 

There are numerous design and cost challenges to overcome, however. Who will design, fabricate, sell, install and repair these systems? What will be the role of window companies? Will they be offered as independent systems assembled and integrated onsite, or as an integrated package delivered to the jobsite?

Another approach that could provide enhanced occupant comfort and health is dynamic control of solar gain and daylighting. This includes: combinations of mechanical shading (interior, exterior or between glass options); passive control using photochromic (light sensitive) or thermochromic (heat sensitive) glazing; or active control using liquid crystal, suspended particle display or electrochromic glazing with an extremely thin coating that switches from clear to colored state with a small applied voltage. All of these involve intelligent control systems that integrate with other building systems in a responsive smart system. 

In addition to bringing the new material technologies online, part of the challenge in taking such developments from the drawing board to the jobsite is forging different supply chain configurations and determining appropriate, cost-effective “packaging” of operational features for different market segments.

The complex business landscape that such innovations thereby imply is certainly part of the challenge. “Perhaps an industry coalition is needed to define the platform and data semantics,” observed Selkowitz. AAMA just may have the beginnings of such a coalition in hand with the formation of the new Innovation Task Group.

Some attribute a quote to Charles H. Duell, commissioner of the U.S. Patent and Trademark Office from 1898 to 1901, stating that the patent office would close in a few years because everything that can be invented has been invented. While this is a clever story, the actual quote is from a religious and literary journal, The Friend, in 1902: “In my opinion, all previous advances in the various lines of invention will appear totally insignificant when compared with those which the present century will witness. I almost wish that I might live my life over again to see the new wonders which are at the threshold.” 

This quote is as true today as it was over 100 years ago.  

Rich Rinka serves as technical manager, standards and industry affairs for the American Architectural Manufacturers Association. Rinka previously worked in the industry as a field technical engineer for a component supplier and developed and holds four patents related to sealants.