save energy
save energy

No matter how hard you try, you can’t fall asleep. The thermometer at home reads 30 degrees and not a drop of air flows through the window. You are experiencing what is known as ” tropical night “, an increasingly frequent phenomenon in Spain.

The climate changeand the transformations that the planet is experiencing in recent decades have triggered the extremes. That means that in summer it is much hotter, and that the minimums do not go down at night as much as they should.

It is a very serious problem that is associated with a dangerous increase in electricity consumption . Because how do you beat the heat when you can’t sleep? Most answer that question by taking command of the air-conditioning.

These then face higher electricity bills , and those who do not even have a device pay less but also rest worse; they perform less well at work, are more stressed, and are generally unhappier. It is a cataract of events.

Therefore, beyond complaining about “how hot it is”, it is worth pausing for a moment on the concept of a tropical night , and reviewing some tips to save electricity during these episodes of night heat. He picks up the fan and continues reading.

What is a tropical night

It’s not just that it’s hot. Scientists have been studying this phenomenon for years and giving it some very specific features. For a night to be considered a ” tropical night ” it must exceed a measurable temperature threshold. This is what the AEMET says :

Gravity Temperature
tropic night More than 20ºC
hot night More than 25ºC
hellish night More than 30ºC


Be careful, we always talk about temperatures at street level; those measured by stations spread throughout the country. It would not be considered a tropical night if it is 26ºC inside your house but it is 18ºC outside. There we talk about heat accumulation .

Because yes, depending on the material with which the walls, ceilings and other structural elements of your house, it will take more or less time to heat the rooms at night.

Tropical nights are becoming more common in Spain

“Well, this will pass.” Yes and no. Although it is normal for tropical nights to last only a few days, the reality is that these episodes of heat are not only more frequent, but also longer and more intense .

A few decades ago, experts calmly affirmed that these events are typical of the ” warmer regions of the planet “. As you already know, the Iberian Peninsula is not among them. Or at least not until a few years ago.

This, of course, also affects the timing of tropical nights. The European E-obs Copernicus observing system shows that between 1961 and 1990 five tropical nights were recorded per year, and that between 1991 and 2020 it shot up to 11 per year .

Come on, today we suffer more than twice as many tropical nights as our parents and grandparents experienced when they were young. What will happen in the future? Projections point to an increase of between 15 and 25% between now and 2050 , and 50% in a century.

Effects of tropical nights on sleep: I can’t sleep

It’s not you, it’s human biology. Science says that from 25 ºC it is practically impossible to fall asleep. Or at least, do it in a healthy way to wake up rested.

Soil expert Christopher Winter leaves the healthy range at 15-19ºC . From 24 ºC we would already begin to have problems, and below 12 ºC we would die of cold without sleeping a wink.

To this we have to add the issue of daylight hours. Every June 23, the summer solstice occurs , which marks the longest day of the year. During the following months the sunrise is earlier and the sunset is later. What’s happening? Well, that also affects us.

So much light alters our biorhythms and deregulates the generation of melatonin ; the hormone responsible for making us feel sleepy, and for relaxing our muscles so we can sleep.

How to save energy on tropical nights

Start by avoiding the temptation of air conditioning. This device thickens more than 30% of electricity consumption in summer, and turning it on at night would only bring us closer to worse figures on the electricity bill.

If you put it on, remember that for each degree less in temperature you will be increasing consumption by 8%. Use it so it doesn’t stay on all night. Bet on him ECO mode and move around 23 – 25ºC.

That said, the best trick to save energy on tropical nights is to run away from any electrical appliances . Also forget about fans, humidifiers and any other device with consumption. You can get perfect sleep without them:

  • Warm shower : No, don’t stand under the shower head to receive a jet of ice-cold water. With that you will only get the body to make an overexertion of regulation (you will have more heat). It is recommended not to go below 18 ºC with the water, and not to spend more than 10 minutes in the shower.
  • Neither mobile, nor coffee nor heavy dinners : Light dinner and several hours before going to bed. Bet on moisturizing and soft foods, prioritizing those that contain tryptophans. If you have already swollen, lie down on the left side because you will sleep better. Oh, and run away from coffee and mobile (or lower the brightness to a minimum).
  • Cotton pajamas and bedding : This type of fabric is our best ally during tropical nights. You will sleep better in a bed with cotton sheets than with polyester counterparts. The same applies to pajamas or the clothes you wear at night. Try putting the sheets in the freezer for a while and you will see the benefits.
  • Do not exercise at night : And if you still want to practice it, try not to finish the exercises with less than two hours to go to sleep. You will activate the body and then it will cost you more to fall asleep.
  • Open the windows : This does not always work because on tropical nights there is usually no breeze. But you can try opening opposite windows to generate a bit of current. Be careful if you get up late, because you will take a bit of sun in the room.

Keep in mind that spending a tropical night in an old 60 m2 house is not the same as spending it in a larger and better-built modern one. Architects point to stone, ceramics, concrete, lime, plaster and clay as good allies.