This article was originally published in the July/August 1995 issue of Home Energy Magazine. Some formatting inconsistencies may be evident in older archive content.



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Home Energy Magazine Online July/August 1995


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What This Country Needs Is an Efficient Small Refrigerator. The Super-Efficient Refrigerator Program (SERP) has been a great success in the promotion of very large efficient refrigerators. However, these SERP units exceed 20 cubic feet, which is just fine for a kitchen in a large house, but not for apartments and smaller households. Now the New York Power Authority (NYPA), with Department of Energy assistance and Consortium for Energy Efficiency sponsorship, is promoting the design and construction of a highly efficient small refrigerator. These two-door frost-free units would have all the standard features packaged in a 14 ft3 refrigerator.

The carrot dangling in front of the manufacturers is potential mass purchases by several public housing authorities, utilities, developers, property owners and managers, and even the federal government. According to DOE's Beth Callsen, The manufacturers claim that they need assurances of about 50,000 units per year in sales volume before they will retool their production facilities for the new design. NYPA expects to purchase 20,000 units, and will allow other bulk buyers to purchase from its contract in order to meet the 50,000 unit threshold.

Goals for energy use of the small refrigerators are less than 500 kWh in 1996 and 400 kWh by 1998. Organizers expect to have models available by the end of 1996. In addition to surpassing DOE standards, these efficiencies could potentially save taxpayers millions of dollars in electricity bills. (Stay tuned for a HE special issue on efforts to improve multifamily housing efficiency.) To participate in the collaborative, contact Beth Callsen, EE-422, Department of Energy, 1000 Independence Ave. SW, Washington, D.C. 20585. Tel: (202)586-9169; Fax: (202)586-1628; e-mail:

Steel-Framing Do's and Duds. The National Association of Home Builders (NAHB) has studied three potential ways to increase the R-value in steel-framed walls and has found that only exterior foam sheathing really helps. (Steel framing reduces wall R-value by about 50% compared to wood framing.) NAHB, sponsored by the American Iron and Steel Institute, studied the effects on a 2 x 4 wall with R-11 fiberglass batts of foam gaskets and hat section furring as well as exterior sheathing. The results on the tests of foam gaskets (intended to reduce thermal bridging by breaking the contact between the steel stud and the drywall) were that they only slightly improved R-value--from R-7.9 to R-8.4--and that they required considerable labor to install. Hat section furring is also used to reduce the contact area between the steel framing and the interior drywall, which is mounted onto the hat-shaped channels, creating an air space between framing and drywall. This method increased R-value by R-1.4. One inch of extruded polystyrene foam sheathing, however, increased R-value by more than the R-value of the foam itself (an increase of R-6.0 with R-5.0 foam).

NAHB also developed a simplified tool for calculating the R-value of steel-framed walls, presented in the Thermal Design Guide for Exterior Walls (published by the American Iron and Steel Institute). If one knows the R-values of the cavity insulation and foam sheathing, one can determine the overall R-value of the wall from a simple chart. The chart shows clearly that the most important determinant of overall R-value is the foam sheathing. In contrast, an increase in cavity insulation (with R-5 foam sheathing) from R-11 with a 2 x 4 stud to R-19 with a 2 x 6 stud raises the overall R-value only from about R-13 to R-15. Even upgrading from 4-in framing to 6-in framing has little effect on the overall R-value. Energy Design Update, Feb and March1995, 235 W 102nd St, #7J, New York, NY 10025. Tel: (212)662-7428; Fax: (212)662-0039.

No-Itch Insulation. Several types of insulation are appearing on the market that are more environmentally sound, less itchy, or just easier to work with. Among these is a fiberglass insulation, Miraflex from Owens Corning, that has blended fibers with random curls that keep them from irritating the skin and getting into the lungs, and make them naturally fluff up more so that no chemical additives are needed. While Miraflex may look and feel like cotton, another newcomer is an insulation batt actually made of low-grade recycled cotton bound with polyester. Greenwood cotton insulation is made mostly of ground-up denim and insulates as well as fiberglass. Roxul's Flexibatts are a form of rock wool, with fibers spun from molten basalt and steel mill slag, but they have a springy edge that holds the batts tightly to irregular framing. Not to be outdone, E2 Development in Burlington, Ontario, has introduced a batt made from 100% recycled PET plastic from soda bottles. Meanwhile spray-in foam manufacturers are busily introducing products that use no CFCs, like Supergreen closed-cell polyurethane and Insealation open-cell urethane. Supergreen is made with HFC134a as a blowing agent, and Insealation uses carbon dioxide and water. Some of these products are not widely available yet, but the market for environmentally improved insulations may grow quickly once people know about them. Popular Science, Apr 1995, 2 Park Ave., New York, NY 10016. Tel: (212) 779-5000; Fax: (212) 779-9468.

A CFL for All Seasons. Just because a compact fluorescent lamp (CFL) is rated for operation at low temperatures doesn't mean that it will shine brightly in cold weather. Starting temperatures and the effect of temperatures on lumen output vary considerably from lamp to lamp, but even many fluorescents rated for outdoors give off little light at very low (or very high) temperatures. This is mainly due to changes in mercury vapor pressure that reduce light output and efficacy. Some new lamp designs, however, are using amalgams--small amounts of compounds such as mixtures of mercury and indium--to help stabilize the mercury vapor pressure inside the lamp and hold it close to the ideal pressure. Lamps using amalgams maintain more consistent light output over a broader range of temperatures than standard CFLs. This means that they operate better at both cold temperatures and hot temperatures (in enclosed fixtures, for instance) than most lamps, whose light output drops off substantially outside of a fairly narrow range of ideal temperatures. Lighting Design Lab News, Spring 1995, 400 E. Pine St., Suite 100, Seattle, WA 98122. Tel: (206)325-9711; Fax (206)329-9532.


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