The Great Debate: does Daylight Saving Time save energy?

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This Sunday, November 3, our clocks "fall back" and we get to sleep in for one blissful hour. While I'm not one to complain about some extra z's, have you ever thought about why we decide to shift our sleep-cycles back and forth twice a year? If you take a look at the history of daylight saving time, the primary goal has been to save energy on incandescent lighting during the evening time. The thinking goes that if the nominal time of sunset and sunrise is pushed back by an hour, people will use less electricity between sunset and bedtime (less time to watch TV!). While this makes sense in theory, the actual effect on overall energy use is widely debated. 

In the spirit of Friday, we present you with three studies, each with disparate results, that attempt to measure the effect of DST on energy consumption.

Increase in energy use

               a. Overall residential electricity consumption increased by 1% to 4%, largely due to additional air-conditioning use in the late afternoon.

               b. Indiana households paid higher electric bills than they did before DST was adopted. Estimated cost was projected at $9 million per year.

No change in energy use

Decrease in energy use

As you can see, the jury is still out. What do you think? Do we still need Daylight Saving Time?