What it costs to run a big-screen TV

Energy usage probably isn’t your top priority when you’re buying a new TV, but it will affect your electric bills for years to come. Home heating and cooling, lighting, and large appliances account for much of your energy consumption, but big-screen TVs are no slouches at sucking up the juice.

Our engineers determined the energy used by typical LCD and plasma TVs turned on for 8 hours a day (yes, a typical U.S. household watches that much TV), 365 days a year. We found little variation between the two display types. Sets of comparable size tended to use about the same amount of energy. That's a change from the past, when older plasma TVs used noticeably more energy than their LCD counterparts.

Size does come into play. It's not surprising, but bigger screens of all types consume more electricity than smaller ones. With LCD and rear-projection TVs, resolution has almost no effect on energy consumption because all pixels in the screen are illuminated by the same backlight. But with plasma sets 1080p models use more energy than 720p models. That’s because 1080p sets have more pixels, each of which is illuminated separately. With LCD sets, the higher the backlight setting, the more electricity used. We set the backlight at the midpoint for our calculations.

Even if the cost differences of a few dollars a month don’t matter much to your budget, keep in mind that the millions of TVs used in American households consume a huge amount of energy. There’s obviously an environmental advantage to using a more-efficient TV.