Spring Forward – Fall Back: Daylight Saving Time

Daylight saving time biannual event where we all feel like we are either losing or gaining an hour of sleep, depending on which way the clock goes. Some of us dread it, some of us love it, and some of us can't quite remember if we are supposed to spring forward or fall back. But no matter how you feel about daylight saving time, one question that often comes up is whether it actually saves energy or not.

First, let's back up a bit and talk about what daylight saving time is. In the northern hemisphere, daylight saving time (DST) starts on the second Sunday in March and ends on the first Sunday in November. During DST, clocks are set forward one hour, so that there is more daylight in the evening and less in the morning. The idea behind DST is that by shifting the daylight hours, we can save energy and reduce the need for artificial lighting.

But does it actually work? Well, the answer is complicated. Some studies have suggested that DST does indeed save energy, particularly when it comes to electricity usage for lighting. A 2008 study by the US Department of Energy found that DST reduced electricity usage by about 0.5% per day, which may not sound like a lot, but can add up to significant savings over time. Another study by the California Energy Commission in 2010 estimated that DST saved the state about 2000 gigawatt hours of electricity per year, which is equivalent to the amount of electricity used by about 200,000 households in a year.