Your Macintosh came with software called ‘Energy Saver’ that allows you to set options for dimming your screen, spinning down your hard drive, and putting your computer in a state known as ‘sleep’ or ‘standby.’ (In this state, your Mac will use up much less power.) These options are useful to conserve power, and so you don’t have to worry about shutting off your monitor or computer. Energy-saving options are especially important on PowerBooks and iBooks that are running on battery power.

Opening Energy Saver

  1. Select System Preferences from the Apple menu.
  2. Under Hardware, click the lightbulb icon labeled Energy Saver.
  3. The Energy Saver preferences pane will open up.


Your Energy Saver preference pane should look similar to the one seen above.It is important to note that there are two settings for each option: Power Adapter and Battery. As you can imagine, Energy Saver uses the Power Adapter preferences when your laptop is plugged into an outlet, and Battery when it is running on its internal battery power. Individual options can be set for each by selecting Power Adapter in the Settings for: menu, or by selecting Battery.

Put the computer to sleep when it is inactive for:

  • This slider will determine how long you can be idle before your computer will automatically go to sleep. As you drag the slider right, the time increases, and a live counter will show you exactly how many minutes you have set. (If you would like your computer to never go to sleep, drag the slider all the way to the right, to Never.)
  • Power Adapter: Bucknell Library & IT recommends a setting of anywhere between 20-60 minutes, depending on how often you want your laptop to go to sleep when it is plugged in.
  • Battery: Bucknell Library & IT recommends a setting of 10-20 minutes. (This will help conserve the power in your battery.)

Use separate timing to put the display to sleep:

  • This slider will determine how long you can be idle before your computer’s LCD screen will automatically dim.
  • If you uncheck this option, your screen will dim when the computer goes to sleep.
  • Power Adapter: Bucknell Library & IT recommends a setting of between 15-30 minutes.
  • Battery: Bucknell Library & IT recommends a setting of between 5-15 minutes.

Put the hard disk to sleep when possible.

  • Checking this option will spin down the hard drive after it has not been accessed in a while.
  • Library & IT recommends checking this option for both Power Adapter and Battery.

Other Options

If you click the tab marked Options, you’ll have a few more advanced options to choose from.

  • Wake when the modem detects a ring will bring the computer out of standby when a device tries to communicate with your computer over the Internet.
  • Checking this option might bring your computer out of sleep more often, but will make sure it can always communicate with other computers.
  • Wake for network administrator access will cause your computer to wake up if your network administrator tries to remotely access your computer.
  • Library & IT recommends checking this option.
  • Restart automatically after a power failure will automatically restart your computer in the event of a loss of power.
  • This is purely up to your discretion.
  • Processor Performance: this menu lets you select the power of your processor.
  • Highest: Your processor will operate at its highest performance and use its full operating power requirements. This setting is recommended when you are using a power adapter.
  • Reduced: Your processor will operate at just over half performance, and use up less power. This setting is recommended for Battery, unless you need the full performance power of your processor.

When you are done setting your Energy Saver preferences, select Quit System Preferences from the System Preferences menu.

For additional information or assistance, please contact the Equipment Desk at 570.577.7733 or

Keywords: Energy Saver, iBook,iMac, MacBook,PowerBook,PowerMac