Does Daylight Saving Time Conserve Energy?

Daylight saving time (DST) is the practice of adjusting clocks one hour forward in the spring and one hour back in the fall. The theory behind daylight saving time is that it would save energy by extending daylight hours and reducing the need for indoor lighting in the evenings.

In 2007, Congress established that DST would begin on the second Sunday in March and end on the first Sunday in November. This year, DST ends on November 2, 2025, as the clocks fall back one hour yet again. As DST comes to an end this year, the question about whether it actually lowers energy usage reemerges.

The belief that daylight saving time saves energy makes sense in theory. If we “spring forward” one hour in the springtime, we’ll have an extra hour of daylight in the evening and won’t need to turn on lights in homes. However, this concept worked better when households had fewer electricity sources. Today, the average family has devices running around the clock — from HVAC systems to televisions, computers, and microwaves. Consumers regularly use far more appliances now than when DST began.

Daylight saving time aims to reduce the reliance on indoor lighting. However, lighting only accounts for 5% of energy usage in U.S. homes, according to the Energy Information Administration (EIA). Heating and air conditioning make up more than 50% of energy consumption, for comparison. And as technology has advanced, American households have evolved in their energy habits. In 2023, the average U.S. household had 17 WiFi-connected devices requiring electricity to run.

So, does daylight saving time actually lower energy costs? Considering the significant changes in energy usage since its passing, and recent studies disproving this claim, it’s unlikely that DST saves a considerable amount of energy.

The legal implementation of DST has gone back and forth since 1918. It was first passed into law under the Standard Time Act on March 19, 1918. This act established time zones across the United States during World War I to reduce energy costs. However, Congress quickly repealed DST in 1919 and left it up to local communities to regulate.

Daylight saving time was re-established during World War II, but its usage still varied until 1966, when the Uniform Time Act standardized times for DST across the U.S. In the following decades, the dates frequently changed for DST until 2007. That year, the U.S. set the currently accepted DST start and end dates in stone.

Today, daylight saving time is a heavily debated topic, with many turning against the practice. Multiple parts of the world have opted out, including most countries in Asia and Africa. In 2022, the U.S. Congress passed the Sunshine Protection Act to eliminate changing the clocks and permanently establish DST. However, the bill did not make it through the House of Representatives. Its future remains undetermined. For now, prepare to “fall back” one hour on November 2, 2025.

When does daylight saving time end in 2025?

Daylight saving time ends on November 2, 2025.

Why doesn’t DST save more energy?

The energy savings during daylight saving time dwindled as society became more reliant on technology. Today, households have dozens of electronics and appliances running at all times. Daylight saving time, in theory, only decreases how much artificial light we use. But it does not impact our usage of other sources of electricity, such as computers, televisions, and heating or cooling.

Which states don’t use daylight saving time?

Hawaii and Arizona do not observe DST. Additionally, several U.S. territories abstain from the practice, including Puerto Rico and the U.S. Virgin Islands.

How can I save energy this winter?

As we move into the fall and winter months, there are several ways to lower your energy usage and prevent higher electricity bills. Consider switching your ceiling fan’s blade rotation, opening curtains during the day to let sunshine in, and performing routine maintenance to weatherize your home.