Once a year, Americans all over the country turn their clocks forward one hour -- an annual ritual called Daylight Saving Time that's supposed to save them money by using less energy.
Except it doesn't. The move to Daylight Saving actually used 1 percent more electricity than if people stuck to Standard Time, according to a 2008 study on residents in Indiana. In other areas of the United States, the time change could cost people even more.
The debate over whether Daylight Saving Time saves money or not has raged since Ben Franklin argued that clock-changing would take advantage of more natural daylight and save candles.
Save on lights, spend on air-conditioning
Unfortunately, old Ben wasn't thinking broadly enough, according to the study, which claims to be the first to use empirical evidence (electric bills) since the 1970s. While Indiana residents saved on lighting by switching to Daylight Saving Time, they spent even more on extra heat and air-conditioning.
During the colder months of Daylight Saving, Indiana residents turned up the heat because they were getting up an hour closer to the coldest part of the night, the researchers found. In the summer months, they cranked up the air-conditioner because they were getting home an hour closer to the hottest part of the day.
The extra electricity cost for Daylight Saving: $3.29 per Indiana household per year or $9 million for the state as a whole. The state lost another $1.7 million to $5.5 million in pollution-related social costs, the researchers estimate.
Those extra costs could be even more pronounced in southern states, where the demand for air-conditioning is higher, according to the study's authors, Matthew Kotchen, a professor of environmental economics at Yale, and Laura Grant, a doctoral student at the University of California, Santa Barbara.
While those effects might be mitigated to some extent by energy savings in commercial buildings, residences are more sensitive to daylight changes, the researchers argue.
Is DST in OT?
So what should happen to Daylight Saving Time?
"Based on our results for residential electricity in Indiana, it would save energy and be cheaper to scrap it entirely," writes Mr. Kotchen in an e-mail.
And Ben Franklin? "We think he might have even reconsidered if he was focused on energy used for heating in his own time," Kotchen writes.