Common Questions

Won't powering my computer on and off hurt it?
NO - This was true on early computer equipment, but not on current equipment.

Doesn't it use more energy to start my computer than it does to leave it running?
NO - The start-up energy consumption is high, but occurs for only a few seconds.  A few minutes of normal operation uses the same amount.

I already use my screen saver, doesn't that save energy?
NO - Screen savers cause your computer to use more energy than they do at idle.

Does MY small energy use really matter in the big picture?
YES - Every little bit helps to make up the big picture!

Turn it OFF or leave it ON?

Do not be afraid to turn off your computer.  According to the Lawrence Berkeley National Laboratory, modern computers are not hurt by frequent shutdowns. Power down the entire computer system (printers and other equipment, too) at night and on weekends: This option will save energy and extend the life of your computer.  It is a common myth that turning computer equipment off and on is bad for it.  Research on current technology shows an improvement in system life when the equipment is turned off, since heat and mechanical stress are the two leading causes of computer failure.  On older equipment (10 years ago) there was concern about power cycling stress, particularly on hard disks, but this is not true on newer equipment.  Equipment will become obsolete long before failure due to power cycling.  Your equipment will also be less vulnerable to damaging voltage spikes cause by weather or power failures when it is turned off.

Screen Savers, Energy Wasters

Screen savers do not save electricity.  They keep your computer’s CPU “awake” and hard drive active, preventing the power management tool from putting your computer into its energy saving mode. 

We tested a 3.6 ghz P4 computer running Windows XP with a 17" LCD flat screen monitor and found that the system used the following:
Computer On and at Idle, Monitor On     - 145 watts
Computer On, Screen Saver Active         - 150 watts
Computer On, Monitor is Sleep Mode      - 105 watts
Computer On, Monitor Off                       - 105 watts

We performed a similar test on a 1.0 ghz P3 computer running Windows XP with a 19" CRT monitor and found the following results:
Computer On and at Idle, Monitor On     - 250 watts
Computer On, Screen Saver Active         - 255 watts
Computer On, Monitor is Sleep Mode      - 110 watts
Computer On, Monitor Off                       - 110 watts

The energy consumption is greater when the screen saver is active than when the system is just ON!  Sleep mode is deactivated the same way that a screen saver is deactivated, by a keystroke or mouse movement, however sleep mode saves as much energy as turning off the monitor.    

Action:

1. Turn off your computer if you are not using it for 1 hour or more.
2. Set power management feature to utilize monitor sleep mode and disable screen savers.  For the most aggressive energy savings use these settings  Max Energy Savings.  Or Click here for Computer Power Management directions.
3. Buy flat screen monitors when ever possible; they use about 1/3 the electricity of a traditional CRT computer screen.
4. Buy Laptop computers when ever possible; they use ¼ of the electricity of desktop versions.