Published: Friday, March 7, 2008
Daylight saving time may not save much energy
For Joyce Swain, daylight saving time means enjoying the outdoors well into early evening.
"My mornings also seem to go better," said Swain, of Port Hueneme, Calif.
Swain and millions of other Americans will have to turn their clocks forward by an hour this weekend. Daylight saving time starts at 2 a.m. Sunday.
Supporters of the time shift say it brings numerous benefits, including more time to exercise outdoors and meet others after work.
But one long-touted benefit -- that daylight saving time reduces energy use -- might not be true.
A study published last month by a University of California-Santa Barbara economics professor and a graduate student found that residential energy use in Indiana went up 1 percent to 4 percent during the months of daylight saving time.
Laura Grant, a doctorate student at UCSB's Bren School of Environmental Science and Management, said Indiana provided her and economics professor Matthew Kotchen with an opportunity to test whether daylight saving time actually reduces energy use.
Until 2006, only 15 of Indiana's 92 counties switched to daylight saving time. Most rural counties chose to stay on standard time, partly because farmers objected to an extra hour of morning darkness. But a law mandating daylight saving time for all counties took effect that year.
Grant and Kotchen compared monthly meter readings of electricity consumption provided by Duke Energy Corp. for millions of households across Indiana before and after daylight saving time was implemented statewide.
The readings showed that electricity use "actually went up during the warmer months, when daylight saving time was in place," compared with earlier years when it was not, Grant said. The study found daylight saving time cost Indiana households $8.6 million more in electricity annually.
While daylight saving time might have reduced lighting needs, "those savings were more than offset by having to turn on the heat during the colder early-morning hours," especially at the beginning and end of daylight saving time, Grant said.
And during the summer, many people turned on their air conditioners when they came home from work an hour earlier and it was still hot, Grant said.
"My mornings also seem to go better," said Swain, of Port Hueneme, Calif.
Swain and millions of other Americans will have to turn their clocks forward by an hour this weekend. Daylight saving time starts at 2 a.m. Sunday.
Supporters of the time shift say it brings numerous benefits, including more time to exercise outdoors and meet others after work.
But one long-touted benefit -- that daylight saving time reduces energy use -- might not be true.
A study published last month by a University of California-Santa Barbara economics professor and a graduate student found that residential energy use in Indiana went up 1 percent to 4 percent during the months of daylight saving time.
Laura Grant, a doctorate student at UCSB's Bren School of Environmental Science and Management, said Indiana provided her and economics professor Matthew Kotchen with an opportunity to test whether daylight saving time actually reduces energy use.
Until 2006, only 15 of Indiana's 92 counties switched to daylight saving time. Most rural counties chose to stay on standard time, partly because farmers objected to an extra hour of morning darkness. But a law mandating daylight saving time for all counties took effect that year.
Grant and Kotchen compared monthly meter readings of electricity consumption provided by Duke Energy Corp. for millions of households across Indiana before and after daylight saving time was implemented statewide.
The readings showed that electricity use "actually went up during the warmer months, when daylight saving time was in place," compared with earlier years when it was not, Grant said. The study found daylight saving time cost Indiana households $8.6 million more in electricity annually.
While daylight saving time might have reduced lighting needs, "those savings were more than offset by having to turn on the heat during the colder early-morning hours," especially at the beginning and end of daylight saving time, Grant said.
And during the summer, many people turned on their air conditioners when they came home from work an hour earlier and it was still hot, Grant said.
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