Reducing power usage and cutting carbon emissions is probably the right thing to do for the future of the planet. But keep this is mind: Green is a powerful marketing term right now and cost-savings promises are part of the marketing pitch. Like all marketing promises, results vary. One example: The amount of money a typical consumer can save by using or powering down energy-efficient computers, printers and the like is often small\u2014in the case of an up-to-date laptop, the energy savings add up to perhaps just $10 a year. \n\nI'm no denier of climate change, but technology users should always be skeptical. Just because a cause seems worthy, accepting conventional wisdom at face value isn't smart. Energy conservation is no exception. \n\nThe purely economic benefits of power-saving lighting, heating and air conditioning systems dwarf the savings to be had by buying an "Energy Star PC," or simply turning off your electronic gear when not in use. Unless electricity gets much more expensive than it is\u2014on average, most customers pay about 10 cents a kilowatt hour\u2014those economics won't change. \n\nEven more disillusioning was the recent news that the vaunted Energy Star certification program run jointly by the Department of Energy and the Environmental Protection Agency is deeply flawed. Unlike many government programs, Energy Star resonates in the minds of consumers, and there's no end of advertising and commentary that tells us to look for the familiar blue logo. [ For more on Green IT, see CIO.com's Green IT Hype vs. The Real Deal and our case study, How Raytheon's IT Department Helps Meet Green Goals. ]So when you learn that government auditors were able to win Energy Star certification by filing bogus applications for non-existent products made by non-existent companies, who wouldn't feel cynical? Sleeping Computers and Saving MoneyWhen a laptop or desktop computer is asleep, your work is in active memory, but the hard drives have stopped spinning, the display is dark and the microprocessor is idle. As a result, power use drops sharply. \n\nA fully awake desktop system made in the last year or two uses some 60 watts of power, but consumes just three watts when asleep. Laptops use less power to begin with, perhaps 20 watts, and that drops to about 2 watts when the laptop is asleep, according to Bruce Nordman, a researcher at the Lawrence Berkeley National Laboratory. \n\nWell, that sounds like it should save plenty of cash. But let's do the math. \n\nTo calculate energy use, multiply the watts by the hours used; divide the result by 1000 to calculate kilowatt hours and multiply that by 10 cents for the average cost of electricity. Do the same calculation for the sleep mode, but remember, your machine won't be asleep 24 hours a day. Instead, let's say that you'll let it sleep 16 hours a day. The result: annual savings of about $10. That's right, annual. The savings on a power-hungry desktop are greater, but still just about $33 a year. \n\nMeanwhile, screensavers not only don't save energy, they waste it. That's because those pretty designs and animations take a good deal of processing power, which in turn requires electricity. \n\nI'm not saying don't put your PC or Macs to sleep. You should, because there's no reason to waste energy. But understand that you'll hardly notice the difference on your monthly power bill. True Story of the Gas-Powered Alarm Clock\n\nI've never been comfortable with the Energy Star system. It reminds me of a pre-school class in which everybody gets an A to be sure all of the kids have plenty of self esteem. Have you noticed that it seems almost impossible to find a more or less mainstream PC that doesn't have Energy Star certification? \n\nSo I wasn't altogether shocked when the Government Accountability Office issued a scathing and funny indictment of the program. Donning the mantle of investigative reporters, GAO staffers submitted applications for 20 or so fake products made by non-existent companies. Fifteen of those products passed muster with the Energy Star bureaucracy, including two that are so hilariously improbable it seems like a practical joke. \n\nOne was a heck of an invention, a gasoline-powered alarm clock, said to be the size of a small generator. "Product was approved by Energy Star without a review of the company Web site or questions of the claimed efficiencies," the GAO wrote. My other favorite: the room air cleaner. The product is depicted as "a space heater with a feather duster and fly strips attached." \n\nThis would be even funnier if taxpayers weren't paying for a program that steers well-meaning consumers to manufacturers who promise, but don't deliver, energy saving products. Or as Senator Susan Collins (R-Maine) who requested the audit put it in an interview with The New York Times: People "are ripped off twice," as consumers and as taxpayers. \n\nThe moral? Your skepticism: don't leave home without it. \nSan Francisco journalist Bill Snyder writes frequently about business and technology. He welcomes your comments and suggestions. Reach him at email@example.com.\nFollow everything from CIO.com on Twitter @CIOonline.