Sleeping Computers Save Money

Sure, reducing power use and cutting carbon emissions are probably good for the future of the planet. But the amount of money a typical small business can save by using energy-efficient computers is small—often well under $100 per year per machine. Even so, if everyone in the U.S. powered down their computers for just eight hours a day, we'd save enough electricity to light more than 2 million houses for an entire year.

Because electricity is relatively cheap, throwing out old PCs and peripherals because they're energy hogs makes no economic sense. The operational cost savings will never equal the up-front outlay. But if you have other reasons to buy new equipment, buying green won't add to your costs.

The easiest way to find a green PC is to look for Energy Star certification. Run jointly by the Energy Dept. and the Environmental Protection Agency, the program aims to identify the most energy-efficient computers—about 25% of those available. Some 42 desktops currently qualify.

If you're already using relatively up-to-date PCs and operating system software, minimize power use by letting your equipment "sleep" or "hibernate" when it's not being used. When a PC 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. A desktop system uses some 60 watts of power fully awake, but consumes just three watts when asleep. (Five years ago, the typical desktop consumed more than five times that much energy in sleep mode.) Laptops use less power to begin with—perhaps 20 watts—and that drops to about 2 watts when asleep, says Bruce Nordman, a researcher at the Lawrence Berkeley National Laboratory.

To calculate how much you'd save by regularly saying nite-nite to your PC, multiply the watts saved by the hours used; divide by 1,000 to get kilowatt hours; and multiply by 10 cents (the price of a kilowatt hour of in most of the country). If your laptop sleeps 16 hours a day, you'll save $10 a year; a desktop, about $33.

The difference in power use between sleep and "off" is not that great, says Nordman. You can save a bit more by turning off your PCs when they're not in use, and despite what you may have heard, turning a computer off and on a few times a day is not going to damage your equipment. Meanwhile, 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.

Many people with older Windows versions had the irritating experience of suffering a crash at wakeup time after putting a laptop to sleep. Newer versions have pretty much solved that problem, as have several generations of Apple's operating system.

Beyond PCs, your office probably has plenty of smaller gadgets and attendant AC adapters. Even when they're not used, adapters drain a small but steady stream of energy, which is why they're known as vampires. The simplest solution is to unplug them when they're not needed. To avoid rooting around in a tangle of cords under your desk, try a smart power strip (Belkin makes one for about $45) with a remote control.

None of these suggestions will save you a huge amount of money, but when multiplied by the tens of millions of computers and other devices in use every day, those 2 million homes could soon be having a very bright year.

To read all of Bill Snyder's columns, go to

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