High-Performance House Discover where products, processes, and systems converge INSIDE:
Thanks to nanoscience, USG was able to make a lightweight wallboard that uses fewer raw materials without compromising performance.
Make the EnergySmart Scale work for you. 47
Build affordable rehabs that are twice as energy efficient. 49
Media of the Month: Energy geeks won’t find anything new in Toward a
Drywall Goes High Tech
A new lightweight product is one of a growing number of building materials that has been re-engineered on the nanoscale.
Engineers are enhancing traditional build- ing materials in ways considered impossible just a few years ago. They’re doing so using the science of nanotechnology, which lets them redesign a material’s basic properties at the sub-molecular level, on scales as small as a few nanometers, or billionths of a me- ter. (A water molecule measures less than a nanometer in diameter.) For example, nano- tech processes let Aspen Technology develop super-insulating aerogels that weigh only slightly more than air. It’s also helping re- searchers at MIT develop a fl exible concrete that won’t crack under stress. Now drywall is getting in on the act. To
create its new Sheetrock UltraLight Pan- els, USG Corp. used nanotech processes to change the way gypsum crystals bond to one another, creating stronger bonds that made it possible to reduce the amount of gypsum in each board without compromis- ing strength. “We developed this product by applying chemical engineering technology to the gypsum crystals at the sub-molecule level,” says Chris Baker, USG’s Wallboard Product Manager. “This allowed us to create a stronger gypsum matrix with a higher
46 GreenBuilder September 2010
strength-to-weight ratio than standard wallboard.” The ½” gypsum board is 30% lighter than
standard wallboard, yet meets the same ASTM strength requirements. USG claims that its light weight and low density also make for a cleaner score and snap. The material’s green story is
the fact that because the new engineered gypsum is stronger, panels can be made with less of it—in fact, about 15% less raw materials have to be extracted from the ground. The boards also have a recycled content of up to 95%, depending on which of the company’s plants produce them. No fl y ash is used. These claims have all been validated by UL Environment, a division of Underwriters’ Laboratories, which certifi es manufacturers’ green claims.
The panels come in standard lengths,
including 8’, 10’, 12’, 14’ and 16’ panels, and in 48” and 54” widths. They cost about 10% more than standard sheetrock.
Zero Energy Home (Taunton Press, 2010). However, most other readers will find plenty of useful information. Detailed chapters cover the main themes of energy efficient building: the building envelope, solar design, renewable energy, HVAC. Although the book is not detailed enough to serve as a how-to, it’s a great primer for builders and remodelers who want to learn how to build low-energy homes—or a helpful review for those of us who have been around for a while. Experienced readers will find the most value in the case studies at the end of each chapter that show how builders and remodelers across the country have put these principles to work. The case studies are presented in the form of 6 to 8 page magazine articles and are illustrated, like the rest of the book, with professional photography. The book’s 13 case studies make it worth buying. Cover price is $16.95, although
Amazon.com has been selling it for $16.97.
Hybrid for Small Homes. Last year, Rheem was first-to-
market with a 50-gallon hybrid water heater that combined an air-source heat pump with a backup electric heater. This June they introduced a new model that puts the same technology in a compact, 40-gallon unit. The HP- 40 is meant for smaller homes and empty-nesters. In addition, lowering the storage capacity by 10 gallons should mean fewer standby losses.
The new water heater has an Energy Factor of 2.0— higher than the new Energy Star minimum standard of 0.67 that goes into effect this month. More information is available at
www.rheempwh.com.
www.greenbuildermag.com
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