This article was originally published in the March/April 1993 issue of Home Energy Magazine. Some formatting inconsistencies may be evident in older archive content.



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Home Energy Magazine Online March/April 1993


Conservation Clips is compiled by Cathlene Casebolt of the National Center for Appropriate Technology, a non-profit organization working in sustainable energy, agriculture, affordable housing, and environmental protection. Conservation Clips contains brief summaries of useful research reports and articles in related magazines, and other publications collected by the NCAT staff. Contact NCAT, P.O. Box 4000, Butte, MT 59702. Tel: (800) 428-2525; Fax: (406)494-2905.



Foam Insulation Materials. As a result of the 1987 Montreal Protocol, which calls for a 50% reduction in chlorofluorocarbon (CFC) production by 1998, many foam insulation manufacturers are striving to reduce the amount of CFCs in their products, and to find suitable alternatives, including hydrochlorofluorocarbons (HCFCs). Because CFCs are locked up in the foam when it's formed, these products will release harmful CFCs into the atmosphere--as they degrade and as buildings utilizing them are demolished--long after CFC production ceases. Besides depleting the earth's ozone layer, CFCs also promote global warming. A single pound of CFC-11 is equivalent to 1,600 lbs of carbon dioxide. HCFC-142b, the CFC substitute used in extruded polystyrene, is still nearly one-third as harmful as CFC-11 in terms of global warming. The rigid foam insulation in an average house with 1 in. of polyisocyanurate on the walls will contribute the equivalent of 22 tons of carbon dioxide into the atmosphere. The 4.5 in. isocyanurate panels used in foam core houses will contribute an astounding 238 lbs of CFC-11, equivalent to 190 tons of carbon dioxide, into the atmosphere. The only boardstock insulation currently available without CFCs or HCFCs are rigid fiberglass and expanded polystyrene. Though rigid fiberglass is probably the best choice, unfortunately it is not widely available in the U.S. The other option is to eliminate rigid boardstock insulation from construction entirely. (Environmental Building News, July/August 1992)

Air Leakage of Barriers. The Canadian Mortgage and Housing Corp. recently studied air leakage of three places in wood framed walls: the header joist, electrical outlets, and window openings. They tested air leakage in each of four construction methods: the poly approach (POLY), the external air barrier approach (EASE), the airtight drywall approach (ADA), and conventional construction. POLY provides an airtight envelope through the use of a polyethylene vapor retarder and acoustical sealant. EASE places the air barrier on the outside of the wall. In ADA, rigid interior cladding materials and gaskets are used to resist air leakage. Conventional panels without air barriers were compared with the other three construction methods. When the joist headers were subjected to simulated winds in a test chamber, air leakage of POLY was 24% of the traditional panel's leakage rates, EASE was 18%, and ADA was 10%. In the window test, all three panels had air leakage of less than 15% of the conventional panel's rates; ADA was lowest, and POLY and EASE were similar. In the electrical outlet test, POLY leaked air at only 24% the rate of the conventional panel, EASE was measured at 16%, and ADA's rates were actually higher than the conventional panel due to the gap in the air barrier around the electrical outlets. Overall, researchers concluded that total air leakage of the three construction methods is less than 20% of air leakage in conventional construction. Window openings hold the greatest potential to increase tightness. (Solplan Review, August/September 1992)

Timber Workers Into Auditors. A program developed by Clallam County Public Utility District in Port Angeles, Wash., has trained 20 unemployed timber workers in residential energy auditing and inspection. Depending on whom one listens to, the reason for the high unemployment rate in Clallam County--upwards of 10.3%--is the Northern Spotted Owl whose forest habitat is now protected, or excessive, unsustainable timber harvests. The program, geared to link conservation with economic development by providing energy training to unemployed workers, consisted of three weeks of instruction in residential energy auditing and inspection. Bonneville Power Administration expects to spend $2.8 billion on saving 1.5 million kW by the year 2000. The need for energy professionals who can make these savings possible strengthens the job market for trainees like the ex-timber workers. (Conservation Monitor, April 1992)

Cloud Gel in Windows. A product to control temperature and light levels according to weather conditions has been developed by Albuquerque, N.M.-based Suntek, Inc. Cloud gel consists of two layers of plastic filled with a clear gel, a mixture of water and polymer, which turns transparent on cold days to admit 90% of incoming sunlight and turns opaque to block 90% of incoming sunlight on warm days. Suntek's president, Roy Chahroudi, believes cloud gel has applications in skylights, greenhouses, and even roofs. Suntek plans to initially market the product for skylights at a cost of about $4 per ft3. (International Solar Energy Intelligence Report, October 5, 1992)


1. Environmental Building News, RR1 Box 161, Brattleboro, VT 05301. Tel: (802)257-7300; Fax: (802)257-7304.

2. Solplan Review, The Drawing-Room Graphic Services Ltd., Box 86627, North Vancouver, B.C., CANADA V7L 4L2. Tel: (604) 689-1841; Fax: (604)689-1841.

3. Conservation Monitor, News Data Corp., Box 900928 Queen Anne Station, Seattle, WA 98109. Tel: (206)285-4848; Fax: (206)281-8035.

4. International Solar Energy Intelligence Report, Business Publishers, Inc., 951 Pershing Dr., Silver Spring, MD 20910. Tel: (301) 587-6300; Fax: (301)587-1081.


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