Study says switch to daylight-saving time in Indiana actually led to more use of electricity

Daylight Saving Time starts March 9. For years, most of Indiana refused to join the rest of the country in moving clocks ahead one hour, "in part because farmers resisted the prospect of having to work an extra hour in the morning dark," writes Justin Lahart of The Wall Street Journal. In 2006, Indiana began participating in the annual switch that has long been considered an energy-saver. Now, research using data from before and after the change says "springing forward may actually waste energy."

University of California-Santa Barbara economics professor Matthew Kotchen and Ph.D. student Laura Grant examined more than seven million monthly meter readings from Duke Energy for southern Indiana before 2006, including a control group of neighboring counties that had chosen to join daylight-saving time on their own because they were in the Central Time Zone.

"Their finding: Having the entire state switch to daylight-saving time each year, rather than stay on standard time, costs Indiana households an additional $8.6 million in electricity bills," Lahart writes. "They conclude that the reduced cost of lighting in afternoons during daylight-saving time is more than offset by the higher air-conditioning costs on hot afternoons and increased heating costs on cool mornings."

Other studies, including one last year in Australia, have found that daylight saving time increases energy use — challenging studies done in the 1970s, including the oft-cited 1975 Department of Transportation report that said an expansion of daylight time prompted a 1 percent drop in electricity use. The difference in then and now is the prevalence of air conditioning. (Read more; subscription may be required)