The PC's Dirty Little Secret: It Wastes Power Shamelessly

But you can buy Energy Star models—and turn them off, too.

The average PC turns half of its energy to useless heat.

The average PC turns half of its energy to useless heat.


Though it is the smartest device in the house, the desktop computer has been dumb when it comes to conserving energy. It's as if every household has a big, gas-guzzling vehicle (or two) in its driveway, all with engines racing. Most people have more computer than they need, says Bruce Nordman, a researcher at Lawrence Berkeley National Laboratory. "It's like we're all driving sport utility computers."

And those hulking, desktop PCs gulp power because they've traditionally been shipped with their throttle stuck wide open. Of course, the energy wasted is more that of a big light bulb than an SUV. But if desktop PCs glowed like their equivalent 150-watt bulb, we'd think to dim them or even switch them off. They don't glow, and few PC owners bother to automatically power them down.

Instead of using its smarts to conserve electricity, the computer instead has embodied the excesses encouraged by once cheap energy. Now the PC industry is scrambling to get green. It's being pushed by big companies, where thousands of office PCs translate small energy savings into big paybacks.

The tougher nut is at home. "Most consumers don't think of the computer as a place to start in saving energy," says Barbara Grimes of the PC industry's Climate Savers Computing Initiative. Home users focus on PC price and performance after years of training to finally master the ins and outs of megahertz and megabytes.

"Low-hanging fruit." Grimes's group launched last summer, just before the Environmental Protection Agency unveiled "Energy Star" standards for personal computers, the first revisions in 15 years. The standards require, for example, that computers make good use of at least 80 percent of the energy they consume. As it is now, PC power supplies on average turn nearly 50 percent of their energy into useless heat. The inefficiency was "low-hanging fruit" in reducing overall power consumption, says Ryan Rasmussen of the 80 Plus Program, a utility-funded bid to promote better power supplies.

Even if Energy Star systems come with a slightly higher price tag, buyers should recoup the difference in a few years of typical use. But the energy savings, maybe $15 a year, can't justify ditching a model that's working. Instead, most consumers can reduce energy wasted as their machines idle. Many home users leave computers on full time, perhaps because of outdated fears of damage from switching them off and on. Worse, more than 90 percent of desktop computers roar at full throttle when switched on. That's because they probably left the factory with energy-saving functions, such as going to "sleep" after some period of inactivity, disabled. Sleep alone can significantly cut a desktop's energy costs, saving about $60 a year. Even laptops, while more energy efficient than desktops, often don't have power management enabled for when the PC is plugged in.

Tips for the settings can be found at Or free programs at or will make the changes and maybe overcome software that stealthily resists letting a PC sleep.

Most PCs now ship with power management enabled, and makers like Dell, Hewlett-Packard, and Apple sell desktops that meet the Energy Star standards. But the industry is awaiting widespread consumer demand. "We think it's right around the corner," says Pat Tiernan, HP's vice president for social and environmental responsibility. But for now, that PC has its engine racing because that's what consumers thought they wanted.