Wasted energy, wasted money
Most of the energy computers use is wasted, since the average
office computer is only used 4 hours each day, but is on for much
longer. Even if you turn your computer off at nights and on weekends,
half of the energy consumed by your computer could be wasted.
If you don't turn off your computer when you go home, your company
could be spending an extra $85 each year for your computer to
do nothing but keep your desk area warm.
Turn off devices when not in use
Leaving your PC and monitor on at night and on weekends is like
throwing money down the drain. Your monitor should always be
turned off when you leave the office since there is no reason
for it to be on if no one is there to see it. Turning off the
monitor alone reduces your computer's energy consumption by about
2/3. If you don't need your CPU for network services or remote
access, it should be shut down, too. SCSI devices, printers and
other peripherals should also be turned off.
Energy Star Computers
Some computers can reduce their power consumption if their power
is left on but they aren't actually in use. This is called power
management. PCs and monitors which can reduce their power to
below 30 Watts can be identified by EPA's ENERGY STAR label.
Look on the ENERGY STAR web pages at
http://www.epa.gov/energystar.html for a list of ENERGY STAR devices.
Using power management
Once power management is enabled, it works automatically. Internal
timers measure how long it has been since you last used the mouse
or keyboard. After a specified amount of time (the length of time
is chosen when power management is configured) most power-manged
computers take a nap--the CPU slows down, and power to devices
is reduced. The monitor, usually on a separate timer, is blanked.
As soon as you hit a key or move your mouse, the computer wakes
back up, right where you left off.
Configuring power management
Sometimes power management can be configured through a control
panel. Power-managing Apple Macintosh PCs have this feature, but
only a few x86-based computers do. Monitor power management can
be set through power management control panels, but can also be
set using an "energy saver"-type screensaver, some video
card control software, or for some monitors even a blank screen
(check the ENERGY STAR list for "universal" monitors).
Most x86-based computers have to be configured through their
BIOS. If you don't know how to configure power management (whether
through a control panel or the BIOS), talk to a computer support
person in your office.
For more information
[References for Energy Star lists, web version of tech guide,
full users guide.]
Continue to Appendix G:
Auditing and Evaluating Power Management in Personal Computers.
Return to the PC User Guide table of contents and home page.
Return to Appendix E: Assumptions for Calculations.