General Question

Afos22's avatar

What color background uses the least amount of power?

Asked by Afos22 (3580 points ) August 8th, 2010

I was thinking about getting the most power out of the battery I currently have in my laptop. Besides switching to “Power Saver” mode and turning my screen brightness all the way down, I was thinking about changing my background to a black screen. Would this use less power than white? or gray? On a side note, would removing my desktop icons also save power?

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15 Answers

MyNewtBoobs's avatar

No and no. Turning down the brightness can help, but not changing the color or removing icons.

Otto_King's avatar

Yes, if you change the background black, that will dramaticaly reduce the power use up. But just google: google black, and you can set up the black google as your start page, and there you can find all the answers about it.

Afos22's avatar

just google?

Afos22's avatar

I’m talking about desktop background.

laureth's avatar

It’s the same amount of light no matter what color, just coming through differently colored microscopic tubes. The lightbulbs still suck up the same amount of power, no matter what color lens the light is passing through.

Response moderated (Unhelpful)
MyNewtBoobs's avatar

@laureth If it’s a laptop, it’s an LCD screen, not a CRT.

Lightlyseared's avatar

@papayalily laureth comments still hold true for LCD. The pixels are microscopic light bulbs and the filters in front of them decide the colour of the pixel.

jerv's avatar

@Lightlyseared That is not my understanding of how a backlit LCD display works. Now an LED is a little light bulb, but LCDs produce no light of their own; they merely filter it.

What uses the most power is the backlight most often a cold-cathode fluorescent lamp. On some laptops, the backlight alone accounts for over 40% of the energy drawn by the system; often more than the CPU and wifi combined. The reason an iPod Touch can play over 30 hours of music but only six hours of video is the backlight, which is usually off for music but always on for video.

Most laptops use a Twisted Nematic (or TN) type TFT (Thin Film Transistor) LCD. With zero voltage applied, they allow light through. As applied voltage increases, they block more light.

As counter-intuitive as it may seem, the most efficient color is white! That is the natural color of a backlit LCD that has zero voltage applied to the pixels; any other color (especially black) requires voltage applied to the pixels to block the backlight’s illumination.

That said, you can get bigger gains by turning your backlight down and setting it to turn off after a short idle period.

Lightlyseared's avatar

@jerv good point, well made

Ivan's avatar

If it’s an LCD, color makes essentially no difference. Black saves power with CRT’s though.

radioethiopia's avatar

Black, because it uses the least amount of light. I recommend www.blackle.com, which is just like Google except it saves energy!

jerv's avatar

@radioethiopia For which type of monitor?

radioethiopia's avatar

@jerv I’m not too sure, I’m sorry!

dabbler's avatar

Lots of good answers out there in particular @jerv and your explanation that white actually uses less power on a backlit screen.
Add to mix for completeness, OLED. These screens actually emit light separately from each and every pixel. They would save power with a black screen since all of the tiny LED lamps is off.
Pretty good bet though that you don’t have an OLED monitor because the ones available are small and Very Expensive e.g. link

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