I heard some time ago about some claims that google should use a black background instead of white, to save power on everyone’s monitors. It sounded somewhat reasonable when everyone still had CRTs, but I was always curious just how much power it would really save.

So, I hooked up one of the energy meters here to my monitor, and displayed a fullscreen black on white terminal, and then a fullscreen white on black terminal. And then back and forth a few times.

• Black screen power usage: 0.188 Amps (@240V)
• White screen power usage: 0.175 Amps (@240V)

How about that. On my monitor at least, (A Benq G222HDL, a fairly generic LED screen) the black background actually uses more power.

The computer itself uses far more of course, and the idle printer/scanner uses 0.051 Amps by itself, so there’s far more savings in switching off than in changing background colours.

Of course, I’m not the first person to question these claims…