In the ’90s, computer experts often recommended leaving your PC on, because you’d shorten the life span of your hard drive by frequently turning the computer on and off. Although hard drives used to have a limited number of on/off cycles, nearly all models manufactured within the last 10 years offer 40,000 or more on/off cycles. For instance, Seagate’s Barracuda 7200.9 line of internal drives are rated at 50,000 start-stops. Thus, it’s unlikely you’ll reach the hard drive’s cycle limit during your PC’s useful life span. On the flip side, the less time you leave a PC on, the longer it will last, because you aren’t consistently taxing the internal hardware.

Another popular PC power myth is that turning your PC on uses more energy than leaving it on. According to the EPA, the small surge of power at bootup is equal to the amount of power your PC would use in a few minutes—much smaller than the amount it’d use if you left it running for a long period of time.

Our last common misconception is that screen savers, which prevent image burn-in on CRT (cathode-ray tube) monitors and plasma TVs, also conserve energy. The opposite is true. The EPA estimates that in 2004, $1 billion was spent on electricity to run screen savers. LCD monitors don’t suffer from burn-in like bulky CRT monitors—making a screen saver unnecessary, outside of its artistic benefits.

What Do Power Experts Suggest?

Factoring in both energy savings and convenience, the DOE suggests you turn off both your computer and monitor if you’re not going to use the PC for more than two hours. In fact, if you have a monitor, printer, or other computer peripheral that go into a standby mode, you can save money by connecting all your computer devices to a single power strip. Devices in standby use a small amount of power, typically between 1 to 10 watts, in order to be ready to respond when needed. By connecting devices to a power strip that you can shut off, such as the Conserve Energy-Saving Surge Protector ($49.99; www.belkin.com) from Belkin (which features a remote control for cutting power), you can further reduce the power consumed by peripherals in standby mode.

If you don’t plan to use your computer within 20 minutes, the DOE suggests that you turn your monitor off and configure the Hibernate or Sleep (Stand By in Windows XP) features included in Windows to automatically power down the computer after a set period of time. Most monitors consume between 25 and 45 watts when on. And with virtually no delay when you turn it back on, it’s not an inconvenience to turn your monitor on and off. That being said, the DOE recommends using the automatic standby modes on your computer, rather than shutting the computer down, to save you from reopening all your programs or waiting for your computer. According to Enesta Jones, an EPA spokesperson, “The value of your time will probably be much greater than the amount of electricity you will save by turning off the computer, if you intend to use it again right away.”

WinXP Power Management Tools

WinXP offers two power-saving options: Stand By and Hibernate. To learn how to power down using the different methods, see "Manage Windows Power Settings” on page 62.

Stand By mode reduces the amount of power used by the hardware on your PC, including slowing down the processor and cutting the power to your hard drive and monitor. The data from your open applications is stored in your PC’s RAM, which allows your computer to return within seconds to the state you left it.

Although Stand By is a low power feature, your computer is still using energy to keep itself ready when you move your mouse, press a key on your keyboard, or push the Power button. With Hibernate, all of the hardware inside your computer is powered down, and Windows stores your open files on your hard drive rather than the RAM. Starting up from Hibernate will take longer than Stand By, because WinXP must start your hardware and load the applications it stored in your hard drive. Load times are usually around 30 seconds, which means it’s longer than Stand By and shorter than starting the computer. In terms of power usage, Hibernate uses around the same amount of power as shutting down your PC. The advantage to shutting down and restarting is that you can reload WinXP, which helps to avoid operating system errors.

Vista Power Management Tools

Microsoft renamed Stand By mode to Sleep, and other than the name change, the primary difference is that Vista’s Sleep mode awakens the computer faster than WinXP’s Stand By mode. Additionally, Windows Vista introduced a new Power button layout. When you click Start, you can select the arrow on the far, lower-right side of the menu to select between Vista’s power down options. You can also configure the Start menu’s Power button to shut down via the method you use the most.

By default, clicking the Power button puts your PC into Sleep mode. To change the Power button’s function, click Start, Control Panel, System And Maintenance, and Power Options. Select the Change Plan Settings link under your current power plan and click Change Advanced Power Settings. Click the plus sign (+) next to Power Buttons And Lid, select Start Menu Power Button, and click the Setting field to choose the power down mode you want. Click Apply and OK. There’s also a Lock button located in between the Power button and arrow, which is ideal when you want to leave the computer on and password-protect your account.

Powerful Ideas

It’s up to you to configure Windows’ automatic power-down options. In WinXP, click Start, Control Panel, Performance And Maintenance, and Power Options. In Vista, click Start, System And Maintenance, Power Options, and click the Change Plan Settings link. Once you choose the type of automatic shut down process you want to use, you’re on your way to saving money, as well as the environment.

by Nathan Lake