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In this file photo running back Danny Woodhead of the New England Patriots fights off a tackle in the Super Bowl on Feb. 5, 2012. The game was the most watched television broadcast in U.S. history.

As millions of Americans huddle around TVs with friends and family this Sunday to watch the Super Bowl, they’ll neglect their laundry, skip vacuuming the carpet and abandon just about anything else that requires electricity, according to a new study. As a result, energy usage will plummet.

During the 2012 Super Bowl, which ranked as the most watched television broadcast in U.S. history with 111.3 million viewers, energy usage dropped 5 percent in the Western U.S. and 3.8 percent in the East, energy software company Opower reported. 

Given all the TVs aglow at once — which collectively consumed 11 million kilowatt hours of electricity during the game, equivalent to the amount of power generated by 10 medium-sized coal-fired power plants — the finding seems counter intuitive, according to Barry Fischer, who conducted the analysis.

The drop in energy consumption is the result of "two related phenomena," he told NBC News.

"One is the fact that we are exclusively focusing our attention in one room, on one appliance, at the expense of doing other energy using activities. Number two is we are doing that exclusive activity together."

Energy usage does increase more than a typical midwinter Sunday in the hours prior to the game — perhaps because people are busy in the kitchen cooking food to munch in front of the tube, and cleaning the house to get it ready for an onslaught of guests.

"But that slight blip upwards is more than offset by the dramatic decrease during the game," Fischer said. 

What’s more, that decrease holds when the game is over, probably because people stay glued to their couches, eyes glazed over and staring at the screen. In the West, where the game ends around dinnertime, people probably socialize for a few more hours instead of going home to do chores.

The study focused just on Sunday, so it’s possible people put off their chores to Monday, but for the big game, the act of getting together with family and friends to watch TV has the benefit of reducing overall energy use.

"While that might not solve the energy crisis, I think it’s an important concept to keep in mind," said Fischer, who plans to head to a Washington D.C. area bar to watch this year’s Super Bowl with friends.

A native of the San Francisco Bay Area, Fischer said he'll be rooting for the 49ers to beat the Baltimore Ravens, though he noted "that did not bias this analysis at all." To learn more about the study, read his blog post. 

 — via New York Times Green 

John Roach is a contributing writer for NBC News. To learn more about him, check out his website.