Dropping brightness levels can save 10-watts continuously, reduce power consumption.

The recent debate over Blackle vs Google power consumption led us to carry out what we consider to be the largest series of tests on LCD monitors so far with 23 LCD monitors giving us incredible useful test results that go well beyond the original debate.

One of the things we found is just how much of a difference the backlight makes to the overall power consumption.

Using our AC power meter, we ran three LCD monitors at both 0% and 100% brightness levels according to their on screen controls. The three monitors were 22-inch Chimei CMV 221H, the Philips 22-inch 220WS8FB and the 19-inch LG W192WS.

We’ve tabulated the results below and from these, you can see that the power consumption range is nearly 3:1 in some cases.

While much of the discussion on Blackle vs Google centred on the few minutes per day that users actually use a search engine, it’s actually possible the achieve a far greater reduction in power consumption by simply running down the brightness levels of LCD monitors.

Now we’re not talking about running them right down to 0% either, although even at that level, LCD monitors still pump out reasonable amounts of light. In practice, we found that on average, by dropping the brightness level from the typical 100% level down to around 65-75%, it is possible to drop the power consumption by around 10W.

Over a 12-hour day, that’s 120-watt-hours. Multiply that by the millions of LCD monitors in worldwide use and you’re talking serious power consumption reductions.

Market analysts DisplaySearch recently announced in June that worldwide shipments of LCD monitors reached 36.6million for the first quarter of 2007.

If each of those saved 120-watt-hours a day, you’re looking at 38.47million mega-watt-hours of every saved.

All by just dropping the screen brightness from 100% to 70%.

Many LCD monitors are shipped with their screen brightness at 100% to give a brighter image but you can easily get away with a 70% brightness level. If you have an LCD monitor, try it yourself and see the brightness difference.

If you can live with it, you’re likely to be saving around 10W in power consumption.

If all 36.6million LCD monitors from Q1 2007 could do that, we’d be cutting power consumption around the world by an enormous amount.