Monitor power consumption basics
Raise your hand if you're not interested in saving a few extra bucks. That's what we thought. Do you want to save the planet, too? Buying the right monitor can't fix the world, but paying attention to power consumption when you buy does help make the world a better place while saving you a few pennies. In these pages, we'll explain why power consumption is important, what you can do to conserve power, how various monitors stack up against each other in power conservation, and how CNET tests monitor power consumption.
Conserving power can save you money
The less power your monitor pulls, the lower your monthly electricity bill. How much lower? That depends on two key factors. The first is how often you use your monitor; not necessarily sitting in front of it, surfing the Internet, gaming, or editing a spreadsheet, but simply how often your monitor is on and showing a picture. The second factor determining how much you're going to save is your monitor's brightness setting, which controls the luminance of your monitor's backlight. The lower you set your brightness, the less power you'll use.
You might not save the world just by turning off your monitor when you leave the house, but you're not helping matters leaving it on, either. By conserving the amount of energy you use, you can reduce the demand for fossil fuels such as coal, oil, and natural gas. Less burning of fossil fuels means lower emissions of carbon dioxide, the primary contributor to global warming. It's as simple as that. And then, of course, there's the money-saving perk. Read on.
How do I conserve my monitor's energy?
Sleep mode is your friend
Make sure that when you're not in front of your monitor, the device is resting up. You can set up sleep mode in Windows by going to Control Panel and choosing Power Options. Select the Power Schemes tab and under Plugged in, change the "Turn off monitor" field to whatever time suits you. (We recommend at least 5 minutes to avoid your monitor nodding off while you're reading a long article.)
Turn down your brightness
Luminance is one of the most important attributes for determining how much power a monitor pulls, and is usually referred to as "Brightness" in your monitor's onscreen display. Adjusting a monitor's luminance affects the amount of light emitted by its backlight. In our tests, we've found that brightness trumps every other setting for saving power; monitors drew the same amount of power whether we were playing a game or watching a Blu-ray movie, as long as the brightness setting was consistent.
You may be wondering how contrast fits into all of this. Truth is, it doesn't. Because the contrast setting only controls the monitor's white level and has nothing to do with the backlight, it doesn't have an effect on power consumption.
If your monitor has a switch, use it
Most LCD monitors do not turn completely off when you press the power button and are still drawing some amount of power. To ensure your monitor is not drawing power, click off the power switch--usually found on the underside of your monitor, near its connection options--if you have one. The power switch acts as an additional level of power conservation. If the power switch is on, the monitor can be turned on by pressing the power button; however, if switched off the monitor can't be turned on--even by the power button--unless the switch is turned back on.
If you're going to be away from your computer for a day or more and your monitor doesn't have a switch, unplug it from the wall to make sure it's not sucking power.
Upgrade from a CRT to an LCD
If you're still using a CRT monitor, consider finally taking the LCD plunge. Not only will it you save money and consume less energy, but you'll also have more room on your desktop for mouse pads, keyboards, and little plush dolls, if you're into that sort of thing.
We tested the Sony GDM520K 20-inch CRT through VGA and based on our test methodology (see how we test LCD monitor power consumption) the annual costs for the CRT are 63 percent higher than the 20-inch wide-screen HP 2009m.
Upgrade from a cold cathode fluorescent lamp (CCFL) to a light-emitting diode (LED)
CCFL and LED refer to the types of backlight in an LCD monitor. Most LCDs use CCFL backlights, which are not as efficient at filling a screen with light from a LED backlight. CCFL backlights consist of several tubes stacked horizontally across the back of your monitor's panel. With LED backlights, there are many individual LEDs all over the back of the screen that can each be turned off or on. This gives LED displays much more precise control over the amount of light coming through the screen, and they are therefore more efficient at energy consumption. LED-based LCDs also have the potential to perform better than CCFL monitors in color accuracy and can be manufactured with much thinner panels than a CCFL-based display.
We tested three LED LCD monitors, the Dell G2210, Dell G2410, and the ViewSonic VLED22. In our tests, the Dell G2210 and G2410 indeed lived up to the LED hype, each earning our Power Saver Seal. The ViewSonic VLED22, not so much. The ViewSonic did not perform badly, just not up to our Power Saver standards (see how we test LCD monitor power consumption).
Get a smaller monitor
We know, playing Crysis on your 30-inch Dell at a 2,560x1,600-pixel resolution is a reason to live, but it's also the reason the power company looks forward to your monthly energy readings. The fewer pixels a backlight has to illuminate, the less power it uses. If you can stomach a smaller monitor, know that it will save you cash.
Panel technology
One more factor that determines how much power a monitor draws is the type of panel it uses. In our tests, we've found that Twisted Nematic (TN) panels pull 45 percenr to 49 percent less juice than Super Patterned Vertical Alignment (S-PVA) models of the same size. Apparently, IPS panels (which usually have a better visual quality than TN panels) require more power for that extra prettiness.
