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When and why do we change the clocks twice a year

The clocks change twice a year and always in the early hours of the morning. On the last Sunday of March, they go forward (at 2am it is 3am) and the last Sunday of October they go back (at 3am it is 2am).

For the last several years, the debate over this measure has intensified between proponents and critics. In fact, everything seems to indicate that the days are numbered for daylight saving time.

The main issues that form the basis of the debate, focus on whether or not we actually save money on our electricity bills and if it is good for our health.

Let’s just remind ourselves of why the clocks change and if it really helps save money on our energy bills.


How do the clocks change?

This is the easy part:

  • On the last Sunday of March, 2am becomes 3am.
  • On the last Sunday of October, 3am becomes 2am.


Who invented hours?

Since ancient times, various civilisations have adjusted their activities in accordance with the sun, dividing the day into 12-hour periods, better known as temporary hours.

This system, based on the hours of sun, was used until the 14th century. Then the first mechanical clocks were made and therefore the days were adjusted to 24 hours. This is how the fixed hour system was introduced.


Who suggested changing the time?

One of the first supporters of changing the time twice a year was Benjamin Franklin, a practitioner of electrical science and an American politician. His favourite phrase was: "Early to bed and early to rise, makes a man healthy, wealthy, and wise".

He realised that, by getting up early, he made better use of daylight hours and therefore saved electricity. Many of his studies and publications focused on how to make the most of daylight hours and how to save energy. However, these publications did not make an impression on people, since there was no fixed timetable for most activities.


When were the clocks first changed?

It wasn’t until the arrival of the railway (end of the 19th century), that fixed times as we know them today were established.

It was the British builder, William Willet, who reached the same conclusions as Benjamin Franklin while riding his horse at dawn. Most of the shutters on houses were closed during the early morning hours, which was a waste of useful daylight hours for homes in England. This concern led him to publish several studies, but his theories were not applied until the First World War.

“Fixed hours came about at the same time as the railway.”

The time was first changed during the war: on the 30 April 1916, all the clocks in the entire German Empire, the Austro-Hungarian Empire, Bulgaria and Turkey, were changed. Later, other European countries and the United States copied the idea.

During the Second World War, the United States ordered the clocks to be changed to save as much energy as possible in war zones. It was also established during the oil embargo of 1973.

Spain did not have a unified time until the 20th century, when the Greenwich Mean Time started being used. Previously, the official time was established by the Madrid Mean Time and the country had various time curves. On 15 April 1918, summer time was officially established, but there were some years (from 1920 to 1923 and in 1925), in which summer time was not applied.

The Civil War brought with it time-related chaos: The Republicans had one time and the Franco-held territories had another. After the war, there were various years in which the clocks were not changed: 1941, 1947 and the entire period from 1950 to 1973. We have been changing our clocks every March and every October since 1973.

“The further north you live, the more energy you save by changing the clocks.”

How much do we really save on our electricity bills?

The aim of moving the clocks back or forward in summer and in winter is to make the most of the natural sunlight. Since the initial studies carried out by Franklin or Willet, it appears to be clear that if we use all the natural daylight hours we should save energy, but, do we really save money on our electricity bills?

There have been several theories recently that question the savings allegedly obtained by changing the clocks, but there are also studies that insist on the need to continue changing the clocks.

In 1975, the United States Department of Transport concluded that electricity usage could be reduced by 1% during March and April, coinciding with summer daylight saving time. Another study from 2011 claims that 1.3 terawatts of power can be saved. This would indicate that annual electricity consumption is reduced by 0.03%.

In Spain, the Institute for Energy Diversification and Saving (IDAE) claims that changing the clocks can save 5% of energy during the summer. Although these percentages may seem small, they could represent significant savings on our electricity bills. In addition, the amount saved in certain regions is apparently greater than in others (the further north, the greater the savings).

Environmental organisations have a very different opinion, together with other studies conducted, which conclude that these supposed savings are not so significant, since more electricity is during used in the afternoon. These changes also have negative effects on the health of people and their productivity at work.


How to save more thanks to hours.

As far as you are concerned, you don’t have to worry too much: it does not depend on you whether or not the clocks change, but you can choose a tariff in which some hours will be cheaper.

It's so cheap that you can pay 0 euros for electricity during the 2 hours of the day that you choose, for 1 entire day per week, or you can choose for the energy to be free during the 50 hours of the month with the greatest consumption. It is called the Tempo Happy Tariff and it will make you happy.

“With all the kinds of changes that have happened over time, we will soon stop moving the clocks back and forward when the autumn/spring .”

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