Imagine a summer evening. The air conditioner hums contentedly, you curl up in fresh sheets and indulge in that rare feeling that this is truly going to be a perfect night. But at three in the morning you wake up chilled to the bone – or sweaty like in a sauna. The culprit? An air conditioner that no one told you that your body behaves differently at night than at 10 p.m. Among the rows of buttons, there is one that most people ignore. And that is a big mistake. So - the button on the air conditioner remote.
Hand on heart: How many buttons on an air conditioner remote do you actually know? Power, temperature up, temperature down, maybe the “cool” mode. The rest is an incomprehensible pictogram with the appearance of mysterious Chinese handwriting for most people. But among them, ladies and gentlemen, the “SLEEP” button sits on the throne – on Samsung it is called “Good Sleep”, on Daikin “Comfort Sleep”, on Mitsubishi “i-Save”, on Panasonic “Quiet/Sleep”, and on cheaper Chinese remotes it is simply a crescent moon pictogram. So – the button on the air conditioner remote.
The feature is standard on virtually all air conditioners manufactured in the last twenty years. Which means you've been grumbling about high bills and poor sleep for years, even though you had the solution right at your fingertips all along. (Slovenian version: "We have it at home, but we don't know!")
Why your body is your personal thermostat at night
To make the story stand on its own, a brief excursion into physiology. The human body has a core temperature that fluctuates throughout the day in accordance with the circadian rhythm – that wonderful internal clock that tells us when to swap coffee for red wine. Before going to bed, our temperature drops by about 1°C, which is a signal to the brain that it is time to rest. During deep sleep, it remains low, but towards morning it begins to slowly rise – a few hours before we really wake up.
Experts, including the American Sleep Foundation, recommend a bedroom temperature between 15.6 °C and 19.4 °C. But if the air conditioner diligently maintains the 18 °C you set before going to bed all night, your body, which is cooled even while you sleep, experiences an unpleasant temperature drop ... and a great morning runny nose. This is exactly where our insignificant button comes into play.
What really happens when you press SLEEP
The feature is not a marketing ploy; it is an algorithm that does three things, and does so with remarkable elegance. First, the air conditioner gently raises the set temperature by about 1°C in the first hour after it is turned on. Second, it adds another one to two tenths of a degree in the next hour. Third, it stabilizes the temperature in the second half of the night or slightly lowers it towards morning – just when your body is preparing to wake up.
In between, the fan is switched to a lower speed (with most brands, the noise is reduced by 3 to 5 dB), and the compressor operates in an economy mode. In short: a quiet, friendly and completely personal night conductor of your rest.
Fewer kilowatts, more dreams: a calculation that will delight your wallet
Now to the money, because sleep also has a price. According to the manufacturer Daikin and several independent studies, the average split air conditioner in an apartment draws between 0.5 and 1.5 kWh per hour, depending on the size of the room and the difference between the outside and inside temperatures. The SLEEP function reduces consumption by 10 to 30 percent throughout the night.
A concrete example: if the air conditioner runs for eight hours and draws an average of 1 kWh, that's 8 kWh per night. With a Slovenian tariff of around EUR 0.18 per kWh, we're talking about around EUR 1.44 per night. Multiply that by thirty days and a 30% savings, and you'll have between ten and fifteen euros left in your pocket. It won't buy you a Birkin bag, but it will buy you a few bottles of good Rebula – and you won't feel guilty because you slept better at the same time.
A small guide to using the SLEEP function for beginners
The ideal scenario goes like this. You turn on your air conditioner twenty minutes before bed and set it to 23 to 24°C – yes, you read that right, not 18. Just before you turn off the lights, you press the SLEEP button and the algorithm does its thing. Many devices also allow you to choose the duration (usually 7 or 8 hours), and some even have a special “tropical nights” profile that regulates the temperature rise more restrainedly.
Bonus points for linen or cotton percale bedding, which works synergistically with the economical climate rhythm and doesn't ruin the aesthetics of the bedroom. A hygrometer (you can find one for five euros) is another great addition: the ideal humidity for sleeping is between 40 and 60 percent, and air conditioning, as you know, dries out a room faster than you would say "menopause."
Five mistakes that make SLEEP mode not work as it should
First: setting the temperatures absurdly low. If you turn the air conditioner to 17°C and expect to sleep for a century, you'll catch a cold. Second time: forgetting to clean the filters. Dirty filters mean up to 25 percent more electricity consumption and anything but quiet operation. Third time: combination of SLEEP function with an open window. Air conditioning is not a gymnast; it cannot win a duel with the August breath from the balcony. Fourth: ignoring the direction of the blow. Blades facing directly into the bed are a classic for sore necks and wet hair. And fifthly: the belief that SLEEP is a winning formula even during heat waves, when it's 35°C outside even at midnight - then you'll need the wet towel trick, an extra fan or a dehumidifier.
Bonus for the truly spoiled: SLEEP + smart home
Modern air conditioners (Bosch, Mitsubishi MSZ-LN, LG with ThinQ platform, Daikin Onecta) offer apps that allow you to activate the SLEEP function with a voice command via Alexa or Google Home. Even better – connect the air conditioner to a smart consumption meter (Shelly, Sonoff, Aqara) and see how much you have saved at any time. The only side effect? When you look at the data in the morning, you will be angry with yourself for not using this function last year.
A bedroom that deserves your best sleep
One tiny button, one giant leap for your nightstand. The next time you're wondering whether to turn off the air conditioner overnight, remember that somewhere among all those unfamiliar symbols is the best night of the week. Now you know it - it's time to finally take advantage of it.
