Net-Zero

Glass From Flat-Panel TVs Makes Zero-Energy Homes More Feasible

Even with the latest windows producing U-factor ratings of as low as 0.11 (roughly equivalent to R-9), windows have quite a way to go before they catch up to solid walls in insulating performance. Meanwhile, a price check on the best windows shows that current costs are prohibitive enough to deter the average homeowner. But a recent report by Rocky Mountain Institute (RMI), an independent, nonprofit organization, suggests that glass borrowed from the flat-panel televisions market is about to upend the costs for triple-pane glass, making it feasible for everyday windows while also making net-zero homes more attainable. The idea corroborates with info gained by Door and Window Market (DWM) magazine from researchers at Lawrence Berkeley National Laboratory (LBNL).

RMI’s report, “The Economics of Zero-Energy Homes: Single Family Insights,” by Jacob Corvidae, Michael Gartman and Alisa Petersen, suggests that, these days, builders can utilize upgrades to building envelopes for residential homes in order achieve net-zero energy performance, to the tune of a 6-8 percent increase in costs—a far cry from the nearly 20 to 30 percent increases previously cited by some experts.

“It’s now clear that zero-energy-ready homes make sense economically today, even as they provide multiple benefits over standard construction,” says Corvidae, RMI’s principal and coauthor of the report. And for this reason, he suggests that zero-energy homes may become the norm sooner than later. “Building anything else today runs a risk of creating homes that will be seen as out of date in only five years,” Corvidae suggests.

In addition to more efficient HVAC, lighting and insulation, RMI’s prescription for cost-feasible, net-zero performance includes the use of triple-pane windows, which researchers say they’ve found to be more economically feasible these days, thanks to what they say is an approximately 80-percent price drop in some of the glass that’s used to produce such products. Those decreases, they say, stem from a crossover from the glass used in flat-panel televisions to the inner-lite of triple-pane windows, dropping their price to as little as $360. According to DWM’s research, that number is on par with the cost of even a middle-of-the-road, double-pane window from just two years ago, when it cost around $236 to upgrade to R-9 performance (the best available at the time). That’s also a number that may decrease going forward, according to researchers at LBNL (see article with full details on page 20), who say they’re closing in on a more than 20-year project, aimed at developing super-efficient, cost-effective, triple-pane windows.

“Twenty years ago we couldn’t find any companies that could make thin glass sheets in volume,” says LBNL researcher Charlie Curcija. “Now the flat screen TV industry has pushed the glass industry to create precisely the glass we need for windows, and at a price the window market can afford.”

CMS Proves 100 Percent Landfill Free Attainable

CMS Window Systems recently set a high mark for door and window manufacturers, by reaching its goal for becoming 100 percent “landfill free”—eliminating any and all waste previously sent to landfills. Officials for the U.K.-based manufacturer say they reached that goal by using a special waste system that separates leftover doors and windows (removed and broken down) into seven different waste streams, including: plastic, mixed metals, timber and glass. Materials are then sent away for reprocessing.

“Hitting our zero landfill target is a tremendous achievement which reflects the focus and effort of everyone in the CMS team to re-use and recycle,” says David Ritchie, the company’s CEO.

“It’s a vitally important milestone in being one of the most sustainable fenestration partners in the U.K. market and is coupled with our strategy to minimize resource use by designing out waste at project inception. Waste is also minimized during manufacture and installation and our range of windows and doors are designed to help our end-customers cut their own energy consumption.”

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