1. Based on a survey of the major U.S. solar hot water manufacturers conducted by Les Nelson, Western Renewables Group, 30012 Aventura, Ste A, Rancho, Margarita, CA 92688. The data agree well with the shipped collector area data reported by the U.S. DOE Energy Information Administration found at http://www.eia.doe.gov/cneaf/solar.renewables/page/solarreport/soltable18.html
2. 2004 Annual Energy Outlook;Energy Information Administration
3. This is an estimate based on average miles driven, gas mileage, and carbon content of gasoline. A calculator for such estimates can be found at various sites including the U.S. Climate Technology Gateway at http://www.usctcgateway.net/tool/
4. The U.S. Solar Rating and Certification Corporation (SRCC) estimates that, on average, for every solar water heater installed, 0.5 kW of peak demand is deferred. See the SRCC Web site: http://www.solar-rating.org/ or write to: SRCC, c/o FSEC, 1679 Clearlake Road, Cocoa, FL, 32922-5703.