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The largest electricity hog in your home may be that little cable, satellite, or DVR box that plugs into your TV. Some typical set-top box setups are serious energy draws—they use more power than a new refrigeratorThe innocuous-seeming gadgets suck up a mind-boggling $2 billion of electricity a year when they're turned "off," according to a released by the NRDC this month.
 
More than 80 percent of U.S. homes subscribe to some form of pay television service, and some 160 million set-top boxes transform the signals into shows, movies, and sports viewed on TVs. NRDC and consultant Ecos monitored the power used by basic set-top boxes and DVRs from service providers including Time Warner, Comcast, Dish Network, Direct TV, AT&T, and Verizon. They found that in 2010, the electricity required to operate all set-top boxes in the U.S. equaled the annual household electricity consumption of the entire state of Maryland; consumed 27 billion kilowatt-hours of electricity (equivalent to the annual output of nine average coal-fired power plants); and resulted in 16 million metric tons of carbon dioxide emissions.
 
The biggest finding, says NRDC senior scientist , was that the only way to really turn these boxes off is to unplug them. Hitting the power button on most boxes tested simply dims the clock or display. A typical DVR consumes 30 Watts when on, and a whopping 29 Watts when “off.”
 
Of course, if consumers unplugged the systems, they wouldn’t draw any electricity. But rebooting the box, much like turning on a computer, doesn’t happen instantaneously. It may take a few seconds or minutes. Or frustratingly longer. Alan Meier, a scientist at Lawrence Berkeley National Laboratory, told The New York Times that when he tried to power down his home system at night, it took “hours” to reboot because the provider “downloaded the programming guide in a very inefficient way.”
  

Source: Better Viewing, Lower Energy Bills, and Less Pollution: Improving the Efficiency of Television Set-Top Boxes
 
Moving forward, the report recommends that manufacturers should design products that meet or surpass Energy Star Version 4.0 (a voluntary program), and design set-top boxes that automatically enter a low-power state when no one is watching a show, or recording one. The products should also wake up in a relatively short amount of time, the authors say.
 
So far, there’s been little incentive for manufacturers and cable and satellite providers to develop and deploy more efficient set-top boxes. Customers are generally unaware of the problem—they do not know to blame the unobtrusive little device for the rise in their electricity bills, and do not choose their boxes anyway,” Elisabeth Rosenthal in the Times.  “Those devices may cause an increase of as little as a few dollars a month or well over $10 for a home with many devices. In Europe, electricity rates are often double those in the United States, providing greater financial motivation to conserve.”
 
Cisco Systems, one of the largest makers of set-top boxes, plans to offer some new models this year that would cut consumption by 25 percent “through reduced power used in ‘on’ and standby states,” reports Rosenthal. “There will be no deep sleep or fully ‘off’ setting. But Cisco said that taking advantage of the potential energy savings for a box would also depend on ‘how it is operated by the service provider.’ Cable and satellite providers will have to decide whether the boxes can automatically go to standby, for example, and whether customers will be able to adjust their own settings. Currently, providers often do system maintenance and download information at night over the cable, so an ever-at-the ready cable box is more convenient for them.”
 
Wondering what you, as a consumer, can do? Call your pay-TV service provider and request a set-top box that meets ENERGY STAR Version 4.0.