Does it drain more energy when screen is white?

There will be a slight increase in energy consumption with white wallpaper as compared to black. This is because the transistors which control the RGB pixels will need to be switched on (and thus use energy) rather than off. The LED backlight will consume the same amount of energy regardless, unless your monitor has dynamic brightness/contrast (in which case the energy consumed by the backlight will vary according to the screen content). Regardless of this, the backlight will be fully energised for a white screen.

Actually it depends how the backlight is. If every pixel has its own LED RGB color then maybe. But if it is just a white LED blacklight that is dispersed across the back then no not really. You can easily test this by putting a completely black background on your screen, if it glows then you have a white LED that disperses across the back of your screen.

Agree with Dwarf.
In theory it probably would.


Remember, Black is not really a color, but the abscence of all color.
White is the presence of all color.

So for a monitor, the pixel would need to be switched completely off to show Black, and switched completely On to show White.
Any other color such as Blue,Green Yellow etc would be a state somewhere between completely Off and completely ON.


Although Im not sure the difference in power consumption would be much of anything to even worry about. Especially with a LED.

Dark images consume more power on an LCD screen.
so if your wallpaper is black, you will use more power.