When thrifty Benjamin Franklin spotted a chance to save precious tallow, he didn't hesitate to pipe up. Franklin suggested that people adjust their sleep schedules in the summer months to enjoy the "economy of using sunshine rather than candles." He jokingly proposed firing cannons to wake people at dawn and imposing a tax on window shutters that keep out sunlight.
Cutting energy consumption—whether because of wartime shortages, oil embargoes, or global warming fears—has always been the justification for the abuse of American sleep schedules. But a new study from the National Bureau of Economic Research finds that daylight saving time actually increases demand for energy. The paper, by the economist Michael J. Kotchen and the environmental scientist Laura E. Grant, takes advantage of a natural experiment in Indiana. The state used to harbor several counties in open rebellion against daylight saving time, but that came to an end in 2006, when a federal mandate forced the counties to fall into line.
Kotchen and Grant estimate that the change cost $9 million a year in higher electricity bills and $1.7 million to $5.5 million a year in pollution emissions. They say the effect is likely to be stronger in other, less temperate parts of the United States.