A typical desktop PC consumes around 200 watts when running—but still as much as 50W when in Windows 8’s “sleep” mode. Even when “turned off,” it can consume up to 20W, as the power supply and some other components remain powered up to perform functions such as wake-on-LAN, said Ideovitra’s sales manager David Chedotal.
In the 6,500 hours a year that the average office PC lies unused, that vampire power consumption can add between 130 and 325 kilowatt-hours to the energy bill. At German electricity prices, that’s anywhere from €30 (US$32) to €90 wasted each year, according to Ideovitra.