June 1, 2005 — Different computers use different indicator lights to signal that they are in energy-saving, or "sleep" mode. Users are often unsure if their PC is truly saving energy, rather than just turning its screen black. To reduce confusion, energy scientists proposed an industry standard, using green for "on," no light for "off," and amber for "sleep." Sleep mode can save up to $150 a year per computer.
BERKELEY, Calif.--Most of us are familiar with the snooze button on an alarm clock. Imagine having one for your computer that's easy to figure out. Scientists have developed a standard that could help you put your computer down for nap. And you'd be amazed at how much money it can save.
Most personal computers have three modes: Off, on, and sleep or stand-by. But do you know the difference?
When a computer screen turns black, the monitor is asleep. But the computer is likely operating at full power.
"They think of it as one device even though it's two separate devices," Bruce Nordman, an energy scientist at Lawrence Berkeley Laboratory in Berkeley, Calif., tells DBIS. He's created an industry standard to show a computer's status, at a glance.
"If the controls are more consistently clear and easier to understand, people might be more likely to use these modes and save a lot of energy," Nordman says.
In the world of traffic lights, green always means go. Red always means stop. Not so in the world of computers, where each brand uses a different word, color or symbol for the sleep mode.
Nordman says, "When you put it to sleep, the indicator light turns to a yellow or amber color. This one goes from green to red. This computer is asleep, and so when it's asleep it pulsates white." His standard uses green for on, no light for off, and amber for sleep.
Sleep mode can save you up to $150 a year for each computer in your house. But until the industry adopts a standard, if you're not snoozing, you could be losing.
You can set most computers to go to sleep automatically by going into the control panel. One final note, even the terminology is inconsistent. Some manufacturers refer to sleep mode as stand by. Check your computer's documents to see how it refers to sleep.
BACKGROUND: After nine years of study, the Institute of Electrical and Electronic Engineers (IEEE) has published a new set of voluntary standards proposing a common set of names, colors and symbols for the power states of computers.
THE PROBLEM: Processing speeds for modern computers continue to increase rapidly, but it has also made the machines gluttons for electric power. And they rarely sleep: in a typical office, about two-thirds of computers operate on full power through the night. Leaving computers on constantly also increases heat gain, and hence the amount of cooling required, wasting even more energy. Many personal computers do feature an energy-efficient "sleep" mode, in which a computer shuts down disk drives, stops sending video signals to the monitor, and closes any idle circuits. But the terminology, symbols, and means of putting computers to sleep vary greatly among computer manufacturers, confusing the folks who buy and use them.
THE SOLUTION: The IEEE's proposed standard suggests three distinct states: on, off and sleep. An on-off switch with have a pictograph of a circle broken at the top by a vertical line; a sleep switch would have a crescent moon. Power lights should be steady green when the computer is at full operation, and amber during sleep mode.
BENEFITS: If adopted, the new standards could save consumers money on their electricity bills, and also spare them the confusion of figuring out the most energy-efficient model when purchasing a new computer. A typical desktop computer draws about 60 watts of power; a conventional CRT monitor adds another 50 watts. When in power-saving mode, however, a typical computer only draws about 5 watts. Over the course of a year, this translates into about $100 savings in electrical costs.
THE HUMAN FACTOR: When it comes to using the sleep mode, having an industry standard may not be all that keeps consumers form using sleep mode. Poorly written software, incompatible accessories, odd combinations of applications or other hitches can cause computers to freeze when powering up from sleep mode.
SCREENSAVERS: Approximately half the power of a personal computer is consumed by the monitor. Screensavers protect the monitor's screen, thus prolonging the life of the monitor, but they do not save on power.
The Institute of Electrical and Electronics Engineers, Inc., and the Human Factors and Ergonomics Society contributed to the information contained in the TV portion of this report.
Note: This story and accompanying video were originally produced for the American Institute of Physics series Discoveries and Breakthroughs in Science by Ivanhoe Broadcast News and are protected by copyright law. All rights reserved.
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