Good news, warm-weather fans: The coolest thing about your next air conditioner may be how much money you save on your summer electric bills. Over the next five years, many residential and commercial appliances -- including water heaters, dishwashers, heating systems, and clothes dryers -- will meet higher energy-efficiency standards set by the Department of Energy. Admittedly, the federal government needed a little encouragement: Two lawsuits filed by NRDC -- along with consumer organizations, the City of New York, and 15 states -- argued that the agency was 13 years behind its congressionally mandated deadline to set stricter efficiency rules. When implemented, the new standards will reduce carbon dioxide emissions by as much as 103 million tons a year, the equivalent of removing more than 18 million cars and light trucks from U.S. roads.