Spain is considering shifting timezones from European Central Time to Greenwich Mean time (an hour back). The country has been an hour ahead of its neighbors since 1942, when then Dictator Francisco Franco changed the national time zone to align with Nazi Germany’s. The idea is to improve Spain’s productivity -- the changes would also mean a more regular work day.
Ironically, Britain -- which is currently on Greenwich Mean Time, has considered shifting an hour forward to be on Central European Time.
In the U.S. we’re not changing time zones, but we are gearing up for our biennial ritual of shifting the clocks -- Daylight Saving Time (November 3rd).
So in advance of that, we ask what is the value of that time trick?
Benjamin Franklin was the first person to observe, in 1784 France, that people (including himself) were wasting daylight by sleeping in through sunny mornings and then wasting precious candles by staying up into the evening. A New Zealander by the name of George Hudson proposed changing the clocks in 1895, but it really didn’t start getting broad traction until an Englishman named William Willett made the argument in 1907.
Germany and the UK implemented it in World War I as a way to save energy (the U.S. ditched it afterward until WWII).
But what about today?
“We found that it costs more to be on day light saving time - about 2-4 percent,” says Laura Grant, an associate professor at the University of Wisconsin. In a 2008 study, she and co-author Matthew Kotchen looked at Indiana residential energy bills before the state adopted daylight saving time in 2006. The bills went up.
Residents might use less to light their homes, but they “also tend to use more AC and heating.”
Similar results turned up in measurements when Australia extended DST in 2000 for the Olympics.
Then again, a California study estimated that DST was saving Californians about 0.5 percent of their daily energy bills. That was based on estimates, not measurements, but David Prerau, author of Seize the Daylight says he’s inclined to think Daylight Saving Time does save energy. He says it does this by 'peak shaving' -- that is, distributing energy use away from peak hours where production is most costly and least efficient.
If It Is Saving Energy, It’s Not A Lot.
One important point to keep in mind: Nobody is arguing that it saves OR costs a lot. We’re talking 0.5-4 percent.
Does It Save Lives?
Prerau says it prevents car accidents. Well, overall at least. Right after the forward clock jump accidents temporarily spike as groggy drivers make mistakes, but in the long run of day light saving time the rate goes down.
He says it also reduces crimes like mugging “the reason is there is very little mugging right after sunrise, but a lot more right out of sunset.”
What About Convenience?
Blogger and marketing expert Nathan Greenberg has written about Daylight Saving Time, he says he became particularly irritated with the “arbitrary schedule changes” after becoming a parent.
“When my son was born it became very difficult to change his schedule -- waking up one day in light and the next day in darkness, babies are creatures of habit,” he says. “Why are we changing something so arbitrary -- we can make the sun rise at noon if we felt like it. Doing this to a child was a big inconvenience.”
Others, like Prerau, enjoy the extra daylight at the end of the day.
But there may be a sort of ‘economic convenience factor’ that we overlook. Severin Borenstein teaches economics at UC Berkeley’s Haas school of business and co-directs the Energy Institute there. He says people change their habits naturally according to timing of daylight, and businesses adapt their schedules to that. Without a unified daylight savings time, stores would change hours haphazardly. Much like a red or green traffic signal, daylight savings time allows them to do so all at once.
“Instead of each company changing hours in different ways at different times, we have a day on which everybody recognizes that we just shift the clock forward,” he says.
So In The End, Why Do We Do It?
There is enough ambiguity in the arguments to lead reasonable people to very different conclusions about the utility of Daylight Saving Time.
“At this point,” says Laura Grant, “I think it’s a tradition and we like that about it and there’s enough inertia behind it to keep it going.”