Monitor Power

by Loyd Case

Q. I want to encourage members of my staff to turn off their monitors overnight. How much money do we waste by leaving a monitor on for 16 hours?—Jane Ford

Power consumption seems to be on everyone's minds these days. As the cost of energy rises, there's a natural desire to want to save money by minimizing energy costs. But the answer to your question isn't as straightforward as it seems. For example, are you running CRT displays or LCDs? CRTs use more power when operating than LCDs do, but use slightly less power at idle (according to a power-management study conducted by Microsoft).

Some people have the absurd notion that using a screen saver will reduce power. That's simply not true. Even a screen saver that puts up a black screen results in no power decrease whatsoever. In fact, some 3D-intensive screen savers, while very pretty, may draw even more power, since they're using the 3D graphics card to render those colorful pixels.

Consequently, you want power management to shut down the display before any screen saver kicks in—or just turn off that screen saver and use your operating system's power management to shut down the monitor. A typical 35-watt LCD will use about 2.5 watts per hour while idle.

Of course, if you have 500 displays, all drawing 2.5 watts per hour, that's around 20,000 watts per night. There's no downside to turning a display off, so if you have a lot of displays, turning them off manually at night is probably a good idea.

Monitor Power - Solutions by PC Magazine