Daylight Savings Time Saves Energy

November 8, 2011 | By | Reply More

There are many reasons for daylight savings time, but the biggest reason is to save energy.

How old is the daylight savings time concept?

The daylight savings concept was around even back when our country was first formed and it was proposed by Benjamin Franklin in 1784 in an essay he wrote, “An Economical Project for Diminishing the Cost of Light.” The basic idea behind his essay is pretty obvious from the title.

When and how did daylight savings begin being used in the U.S.?

When Congress created the Department of Transportation in 1966 it transferred responsibility for time laws to this new department. It was in that same year that the Department of Transportation created the Uniform Time Act which is the law by which we turn our clocks back in fall and forward in spring. This law doesn’t require observance of daylight savings, but states that if it is observed, it is to be observed uniformly. Since 1966, the rules and laws regarding daylight savings have changed many times for many reasons. In the 1970’s the U.S. Department of Transportation conducted studies that showed that it is possible to trim our entire country’s energy usage by about one percent each day that daylight savings is in place. The California Energy Commission conducted a study to see if creating an early daylight savings time or going to a year-round daylight savings time will help with the electricity problems California faced in 2000-2002. Later, in May, 2007 the Energy Commission conducted another study, “The Effect of Early Daylight Saving Time on California Electricity Consumption: a Statistical Analysis.”

How does it save electricity?

The basic idea behind the daylight savings time works like this. In general terms, the amount of electricity we consume in our homes is from lighting and small appliances. We use the lighting and appliances in the morning after getting up but before leaving for work or school, and then again in the evening after returning home but before going to bed. Most of this energy is actually consumed in the evenings and not in the mornings.

With Daylight savings in place during summer months, it’s as if the sun sets one hour later, reducing the period of dark time between sunset and bedtime by one hour, and resulting in less electricity is used for lighting and appliances. Plus people tend to spend more time outdoors in during summer months when the sun sets later. True that we will use more electricity in the morning because of the sun rising later, but the studies show that the savings in the evening electricity more than offset the morning loss.

During winter months the sun sets earlier and we turn daylight saving off by turning the clocks back by one hour, once again increasing the amount of daylight we have in the evening before bedtime.

The shortest days of the year occur during November, December, January and February. During these months with daylight savings time turned on or off, the savings in the evening would equal the loss in the morning and so there is no savings during those four months.

What is the total net savings?

The gains are small for each household. It’s greater during some months and less during others. The overall savings is probably somewhere near the one percent savings projected by U.S. Department of Transportation studies in the 1970’s. It may not sound like much, but consider this. According to the U.S. Energy Information Administration, in 2010 the U.S. consumed 3,884 billion Kilowatt hours. One percent of that amount is truly an impressive savings.

Does daylight savings really save energy?

Well, there was study and subsequent report created by University of California, Santa Barbara that showed in Indiana, daylight savings actually caused the usage of more electricity. Later analysis conducted by staff of the California Energy Commission says a similar study may not yield the same results for California because of a variety of conditions in California that are not the same as in Indiana.


Benjamin Franklin’s Essay:

2001 California energy study conducted by California Energy Commission

2007 California energy study conducted by California Energy Commission

2008 Indiana energy study conducted by University of California, Santa Barbara

2008 U.S. Department of Energy study

Your Thoughts …

If you have an opinion on daylight savings time, we’d like to hear it. We’d also especially like to know about daylight savings plans in other countries. Let us know.



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Category: Energy Tips, General Energy Information

About the Author ()

I am in my second year of a five year combination BS physics/math and MS systems engineering program offered jointly through Haverford College and UPenn. Helping my community is a lot of fun and means a great deal to me. Through the IEA and other efforts, I've come to learn how much power many can have when there is a clear positive vision, motivation and momentum. "There is no sadder sight than a young pessimist." — Mark Twain

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