Change way you use PC, save a bit on electricity



Electricity is on everyone's mind this summer. When the weather's bad and power lines go down, we can't get enough of it. And when we do have enough, we'll be paying a lot more for it than we did before.

Both issues brought calls from readers of last week's column on protecting your PC from the vagaries of summer weather. Some chided me for neglecting the most foolproof way to protect a PC from a thunderstorm. Others noted that customers of BGE are facing huge increases in their electric bills and wondered if there's a way to use less power to run their home computers.

First things first -- although surge suppressors and uninterruptible power protect a computer from power surges, nothing is as good as unplugging it. Lots of folks do this when thunderstorms are in the area, or when they leave home for the weekend or vacation. I feel like an idiot for leaving that option out of the column.

Now for the tougher question.

With electric bills in Baltimore set to increase by 72 percent over time, should you change your computing habits to save money? The answer: You won't save enough to pay for college tuition or affect your retirement, but within reason, it's a good idea to conserve.

At the outset, remember electricity is billed by the kilowatt hour (kwh). That's how much juice a 100-watt bulb uses if you burn it for 10 hours.

Before July 1, Baltimore-area residents paid an average 8 cents per kwh. But over the weekend, the full rate went up to 14 cents per hour. Thanks to a temporary relief plan enacted by the General Assembly, the effective rate now is about 9 cents per kwh. But that's only a deferral. We'll wind up paying most, if not all of it back over a period of years. So figure 14 cents.

Now determine how much it costs to run your PC.

Depending on what it's doing at the moment, the average desktop computer consumes 60 to 120 watts of electricity.

Playing a game, downloading a large file or some other activity that keeps the microprocessor running and the hard disk turning uses more electricity than sitting at idle.

A cathode ray tube monitor adds another 80 watts, on the average, while a flat-panel, liquid crystal display (LCD) uses only 22 to 25 watts.

For the sake of argument, I'll put our hypothetical average consumption at 180 watts, or 0.18 kilowatts. At 14 cents per kwh, the cost works out to about 2.5 cents per hour for a computer and monitor. Of course, your mileage may vary.

If you're a casual home user who keeps a computer running four hours a day, you'll pay $36.50 a year under the new rates, compared with about $21 under the old rates. If you leave the computer on for 12 hours, it will cost about $110 a year, compared with $63 under the old system.

Other devices, including routers, cable modems, printers and scanners, use a couple of watts, too. Even so, when I consider that the four recessed lights in the ceiling of my home office use 300 watts of electricity -- far more than all of my computer equipment combined -- the PC is relatively cheap to feed, even under the new rates.

Best method

That said, the best way to save money is to make sure your computer is turned off at night. This gets into one of the oldest debates in personal computing, but given the increased cost of electricity, the odds are strongly in favor of flicking the switch.

You can also save electricity by using the power management features built into Windows XP and earlier versions of the operating system.

Many laptop owners already use these settings to extend battery life -- although laptops are so frugal that power management has little impact on operating cost.

Desktop computers rarely have these features turned on. Enabling them on a machine that runs eight hours a day or more can conserve electricity and save a few dollars.

To access Windows' power management seetings, open the Windows control panel and select Power Options. What you see will depend on your equipment and version of Windows. Laptops, for example, have more options than desktop machines because they operate on batteries as well as standard AC.

Windows offers two types of low power settings that can take effect after a period of inactivity ranging from a minute to five or six hours -- you get to pick that.

For relatively short periods of down time, "Standby" mode turns off the monitor and hard drive -- which use most of the electricity -- but leaves the PC's internal circuitry and memory warm. All open files and application programs remain open, too. So if you lose power, everything in memory that hasn't been saved to your hard disk will disappear.

Standby allows you to resume work relatively quickly -- it may take only 15 or 20 seconds to turn on the monitor and get a hard drive up to speed. But Microsoft doesn't recommend using it for longer periods, such as overnight.

About `Hibernate'

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