Daylight Saving Time (DST) was originally implemented to save energy because of less need to use lighting in the evening hours.

The Energy Policy Act of 2005 added four weeks (three weeks earlier and one week later) to daylight saving time, making it extended daylight saving time (eDST).

Originally DST was from the first Sunday in April to the last Sunday in October. Now, eDST goes from the second Sunday in March to the first Sunday in November.

However, almost all of Indiana didn’t accept this new time change until spring of 2006 because its farmers had lobbied against it in its first year. Only 15 of 92 Indiana counties accepted eDST in the spring of 2005, while all of Indiana accepted it in 2006.

Thus, Kotchen and Grant compared seven million monthly energy bills from Duke Energy Corporation in southern Indiana over a three-year period involving when Indiana didn’t and did use extended daylight savings time.

Kotchen and Grant found that the use of electrical energy for lighting was reduced in the spring, but there was an increase in the use of electrical energy for cooling and heating in the summer and fall. The increases in energy were greater than in the decreases in energy use, making it more expensive for Indiana to use the extended daylight-saving time plan.

In fact, about a one to four percent increase in energy consumption resulted.

The researchers found that eDST actually costs the citizens more energy, $3.19 per household for a total of $8.6 million.

However, in a Wall Street Journal article (“Daylight Saving Wastes Energy, Study Says”), Massachusetts representative Edward J. Manley says that study is flawed. He states, the study “cannot accurately asses the impact of [daylight-saving time] changes across the nation, especially when it does not include more northern, colder regions."

Kotchen and Grant note that additional research is necessary to validate their conclusion. They would like a similar study in states with high energy consumption, like the western state of California, and the southern states of Florida and Texas.

According to an Associated Press article, Kotchen said, “The point of this study is just to shed light on the old myth that Daylight Saving Time saves energy.” [Galesburg Register-Mail: “Adjust clocks – internal and external”]

Another study conducted in Australia helps to support Kotchen and Grant's conclusion. Please read on.