Representatives Edward Markey and Fred Upton, who sponsored the amendment to the 2005 Energy Bill requiring the change, said it was expected by 2020 to save 4.4 billion dollars in energy bills and avoid the need to build more than three large electric power plants.
They said it also would save 279 billion cubic feet of natural gas, and avoid nearly 10.8 million metric tons of carbon emissions because people consume less electricity in the evening if it is still light.
"The change in the beginning of daylight saving time is just one step towards making our country more efficient in its usage of energy and conscious of our environment," Markey said recently.
"Not only will Americans have more daylight at their disposal for four additional weeks in the year, but we will also see wide energy saving, less crime, fewer traffic fatalities, more recreation time and increased economic activity. Ultimately, daylight saving just brings a smile to everybody's faces."
Others are not smiling. They say U.S. and international businesses have been slow in updating critical computer systems. They say it might lead to inaccurate times for financial transactions, potential delays in airline flights and other headaches.
"We fear that some high-risk organizations are not well prepared," said Andy Kyte, research vice president at the consulting firm Gartner Inc.
"This is not Y2K-scale, but it could generate business procedure and IT system problems that modestly disrupt smooth business operations, irritate customers and tarnish professional reputations."
Unlike the year 2000 (Y2K) bug, which generated wide publicity and prompted considerable upgrades, this change has gone relatively unnoticed. But because the U.S. change comes at a different time from those in Europe and elsewhere, it has the potential to create some problems.
Gartner said multinational organizations or those with customers and suppliers inside and outside the United States face a "significant risk of continuous minor irritations and glitches that will negatively impact IT and business efficiency."
The consultancy said these organizations should bring in IT staff over the weekend to cope with any glitches and "avoid major IT initiatives during the weekend."
John Challenger of the consulting firm Challenger Gray and Christmas said the problems could spill over to Monday, with a bleary-eyed workforce struggling with one less hour of rest. He said productivity may be down as much as 30 percent Monday.
"Not only will this catch many Americans off guard in terms of their sleep habits, but information technology experts are predicting some computer glitches related to the early shift," Challenger said.
"The glitches are not expected to be major, but they could be enough to slow the pace of work on Monday."
Some say the surprise may hurt an already sleep-deprived American public.
"Millions of Americans already do not get the sleep they need," said Richard Gelula of the National Sleep Foundation, urging people to set aside time for nine hours of sleep.
"And, unless we choose to make sleep a priority this weekend, daylight saving time will take away yet another hour of healthy sleep."