This article was originally published in the September/October 1993 issue of Home Energy Magazine. Some formatting inconsistencies may be evident in older archive content.
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Home Energy Magazine Online September/October 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.
Puget Power's Conservation Reductions. Puget Power and Light will no longer fund residential heat pumps, retrofit thermostats, or insulated doors, as a result of its new total resource cost (TRC) test. The test, effective April 1, 1993, determines a measure's cost-effectiveness by taking all associated costs into account (including customer expense and utility payments) and weighing them against the measure's total benefits (including electricity savings and Puget's avoided cost). If total costs outweigh total benifits, the utility won't fund it. Prior to implementing the TRC, cost-effectiveness was based only on Puget's cost. In addition to eliminating those measures, the utility will decrease funding for several other measures as a result of the TRC. Changes are also expected in the commercial and industrial sector. Puget is allowing a grace period for customers to install measures soon to be discontinued. Conservation Monitor, (April/May 1993), News Data Corporation, Box 900928, Queen Anne Station, Seattle, WA 98109. Tel: (206)285-4848; Fax: (206)281-8035.
Electric Water Penalties in California. Title 24 of California's building code requires new buildings to meet an energy budget through measures such as energy-efficient appliances, insulation, and fenestration products. Measures that reduce energy consumption are assigned positive points, and those that increase it are assigned negative points. Trade-offs between measures are allowed, but the total points (taking all measures into consideration) must not fall below 0 in order to comply with the code. In revisions to the code, electric water heaters create a substantial point deficit, (about -20 for a 1,600 ft2 home), which is difficult to offset in other areas of the building's design.
More practical options are gas- and propane-fired water heaters and heat pump water heaters which, in a 1,600ft2 home, have a point value of +1. Woodstove boilers constitute another option. Heat pump water heaters, considered the most energy-efficient systems, are about three times as efficient as electric resistance systems. In addition, these systems supply free cooling, which means reduced air conditioning costs in summer (though in winter, the heat comes from the heating system). Heat pump water heaters are not widely used in California, largely because customers aren't aware of their advantages. Electric Water Heating News, Winter (1992-1993), EPRI, P.O. Box 10412, Palo Alto, CA 94303. Tel: (415)855-8950; Fax: (415)855-2954.
Ozone and Indoor Pollutants. Through a study led by Charles J. Weschler, scientists have discovered that smog ozone promotes volatile organic compound emissions in nylon carpets. The study revealed that ozone can infiltrate buildings--in some cases, nearly equaling outdoor levels--and then interact with indoor materials such as nylon carpets and backings. In the four experiments conducted for the study, a stainless steel reaction chamber was carpeted. A ventilation system changed the air inside the chamber once each hour. Scientists measured VOCs for a week and then introduced ozone to the chamber. When the ozone had stabilized (28-44 parts per billion), air samples were taken again. The results showed that emissions of formaldehyde and acetaldehyde (both suspected carcinogens) were three and 20 times greater, respectively, when ozone was present. Ozone also stimulated other aldehydes by reacting with the carpet's nylon pile. Worth noting, though, is that the ozone reduced several other VOCs from carpet adhesives and backing, including the one causing new carpet odor. Science News, (December 19 and 26, 1992), 11719 N St. NW, Washington, DC 20036. Tel: (202)785-2255.
Indoor Air Quality Sensor. Ventilation unquestionably ensures good indoor air quality in tight homes. Fresh air can help dilute pollutants, but it may not be enough. To help solve more serious indoor air quality problems, Gaztech International of Goleta, California, has developed a new ventilation controller that introduces more fresh air when it senses an excess of certain pollutants such as carbon dioxide and carbon monoxide as well as a rise in indoor humidity. The system--the Venostat 2001 Series--is based on Non Dispersive Infrared Technology, which has been used in medical and gas-sensing products for more than 40 years. Through infrared radiation, the sensor can identify gases with polyatomic molecules, which diffuse through a membrane into a sampling chamber in the product. When too many of such molecules are present, a microprocessor calls for more fresh air. Popular Science (February 1993), 2 Park Ave., New York, NY 10016. Tel: (212)779-5000; Fax: (212)779-9468.
Exhaust Appliances and Backdrafting. While powerful exhaust appliances in tight homes can help remove indoor pollutants, they can also cause indoor air quality problems. A case in point: After becoming ill at the beginning of two heating seasons, a homeowner in Vermont suspected that his new house was causing his illness. He began operating his 500-cubic-foot-per-minute range downdraft fan to help remove the pollutants. However, an investigation by Central Vermont Public Service Corporation revealed that the range fan was actually to blame--it depressurized the house, which ultimately caused the oil furnace to backdraft.
One way to solve such problems is to eliminate chimneys and natural draft combustion appliances altogether. Builders in British Columbia, however, are trying a different approach--installing fresh air supply fans to offset depressurization caused by exhaust fans. In fact, building codes there require this design feature in new homes with chimneys. The same thing is required of consumers participating in BC Hydro's new construction and retrofit energy programs. Energy Design Update, (March 1993), Cutter Information Corporation, 37 Broadway, Arlington, MA 02174. Tel: (617)648-8700; Fax: (617)648-8707.
Heat Recovery Not Cost-Effective. Heat recovery ventilators can provide mechanical ventilation in tight homes and, at the same time, retain 50%-90% of the heat in the exhaust air. However, two studies, one conducted by the Northwest Power Planning Council for the Super Good Cents Program, and the other by the State of South Dakota, found that heat recovery ventilators are not cost-effective in milder climates. Some of the reasons cited are high installed cost, low system efficiency (about 55%-75%), and higher infiltration levels in homes. To determine whether a heat recovery ventilator is appropriate, factors such as ventilation rate, energy costs (including electricity costs of defrosting the heat recovery ventilator in a cold climate), and heating system efficiency must be taken into account.
For example, a 2,500ft2 home in an annual 7,000 heating degree-day climate, with a 95% efficient propane furnace (and with fuel cost as low as 65cents per therm) and with an hourly air change rate as low as .25, would pay only about $90 in annual ventilation energy costs. A $3,000 heat recovery ventilator system would take 32 years to pay for itself--not a very cost-effective investment. On the other hand, in colder climates, such as Saskatchewan with 12,000 annual degree-days, heat recovery ventilators offer considerable energy savings. Indoor Air Review, (October 1992), IAQ Publications, Incorporated, 4520 East-West Highway, Suite 610, Bethesda, MD 20814. Tel: (301)913-1005; Fax: (301)913-0119.
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