Thursday afternoon during the Insulating Glass Manufacturers Alliance’s (IGMA) Winter Meeting, attendees were invited to participate in a “Glass Performance for Energy-Efficient Fenestration” panel. Bill Lingnell of Lingnell Consulting Services and IGMA technical consultant moderated the panel that included David Cooper of Guardian Industries, Jeff Haberer of Trulite Industries and Chris Barry, consultant.

“When we look at the performance [of glass] today, there isn’t much more we can do with the current technology. We have some low-E products that have the lowest emissivity you can get … where are we going to go two, five or 10 years from now?” asked Bob Spindler of Cardinal.

“We’ve still got a little ways to go. We haven’t reached the end of the road where things can’t get better,” said Lingnell.

“Bob’s right,” added Cooper. “The ability of coated glass, high-performance coated glass, is reaching its end-point for coating a single piece of glass … a standard vacuum insulating glass (VIG), triple VIG is possible technology … I predict within 10-15 years something such as a triple VIG will be out there that’s feasible and gets the glass package up into that R20 range.”

“A lot of things have been tried but nothing’s come out of it,” said Haberer. “There is technology that is existing, we just haven’t brought it to a point to be able to market it, but I think that’s going to happen.”

“Low-E improves insulation and reflects far infrared,” said Barry. It’s not for solar control. We have to go a step further. We can’t just chase U-value. The answer is not U-value or solar heat gain coefficient (SHGC). It’s energy. That’s what we’re really worried about. Stop wasting energy … you won’t do that with a very good U-value or SHGC.”

Later that afternoon, Randi Ernst with FDR Designs presented his findings on gas fillings. Among the discussion of gas, including the reasoning behind the use of argon over most other gases, as well as the key to proper gas fill performance, Ernst involved attendees with a variety of demonstrations. One included an air gun shot at a balloon, balloon races using a balloon filled with sulfur hexafluoride (SF6) versus a helium-filled balloon—SF6 won—and tubes replicating the gas placement and filling in units. Following the presentation, attendees were treated to ice cream made using liquid nitrogen.