The following information is from the U.S. EPA's Energy Star Purchasing Tool Kit
General
By leaving the machine on around the clock, you run up your electric bill, you
suck in dust and you make yourself more vulnerable to power surges. An
Energy Star label is not a guarantee that your machine is saving energy.
Always check to ensure that the Energy Star features are enabled.
Computers
A well-designed Energy Star-compliant computer will not lose its network
connection, which could lead to a loss of data, while in the low-power or sleep
mode. Most of the computers that are being manufactured today include a
capability to sleep intelligently on a network. The new Energy Star
specifications, effective July 1, 1999, require all computers that are shipped
with network capability to sleep on networks and to respond to computer requests
to wake up.
Monitors
Switching on and off the monitor five times or more a day increases the
frequency of faults in power transistors in the control and deflection parts
only after the machine has been used 20 to 30 years.
Screen Savers
Despite common belief, a screen saver does not save energy. In fact, more
often that not, a screen saver will not only draw power for the monitor but will
also keep the CPU from shutting down.
Games
Many popular games, when running in the background while multitasking, will not
allow the computer to go to sleep--even if the game is paused.
