Many people have developed the habit of setting their air conditioners to 28–29°C at night, believing it helps save electricity and is better for their health. But is this really true? Let’s take a closer look at what science and experts have to say.

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The Benefits of Sleeping with the Air Conditioner On

In developed countries, air conditioning has become an essential part of modern living, providing comfort and improving sleep quality. Using an air conditioner helps you fall asleep faster, enjoy deeper rest, and recover better after a long, exhausting day.

When the room temperature is balanced with your body’s natural comfort range, you tend to sleep more soundly. However, as you enter deep sleep, your body temperature naturally drops. That’s why it’s important to use a light blanket or duvet to prevent getting too cold at night.

Interestingly, sleeping in a cool environment can even support weight management. Research has shown that cooler temperatures help boost metabolism and promote the conversion of white fat (which stores energy) into brown fat (which burns energy).

Moreover, studies indicate that sleeping under an air-conditioned environment with moderate cooling can aid detoxification, tissue repair, and even help alleviate symptoms of chronic pain or neurological disorders. It also improves mental well-being, particularly for those struggling with stress or mild depression.

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Does Setting the AC to 28–29°C Actually Save Power?

According to HVAC experts, an air conditioner works most efficiently when the outdoor temperature is below 48°C and the indoor temperature is at least 19°C or higher. To optimize energy use, your indoor temperature should ideally be 6–10°C lower than the outdoor temperature.

This means that if it’s 40°C outside, setting your AC to around 30°C will keep your room cool while conserving electricity. However, when it’s 30–35°C outdoors, the ideal indoor range should be 25–28°C. Setting your AC too high, such as at 30°C, may cause the outdoor compressor to switch on and off repeatedly, which actually consumes more electricity due to frequent restarts.

In contrast, setting the temperature too low (for example, 24–25°C) forces the compressor to run continuously at maximum power, which leads to higher electricity bills and increased wear on the system.

To save energy and protect your health, you should activate the “Sleep Mode” feature on your air conditioner at night. This function automatically increases the temperature by 1°C after 30–60 minutes, and then again after another hour or two. This gradual adjustment prevents you from feeling too cold in the middle of the night and helps the system run more efficiently.

For example, you can set your AC to 26°C before going to bed and turn on sleep mode. After one hour, the temperature will automatically rise to 27°C, then to 28°C after two hours—perfectly adapting to your body’s cooling rhythm during deep sleep. This not only ensures comfortable rest but can reduce electricity consumption by up to 15–20% over time.

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Additional Tips for Using Air Conditioning Safely and Efficiently

• For children and the elderly: Their immune systems are more sensitive, so limit air conditioner use to about 2–3 hours at a time. Let the room rest for 30 minutes before turning it on again, and never allow cold air to blow directly onto their bodies.

• After outdoor activities: When returning from hot weather, wait at least 5 minutes before entering an air-conditioned room to allow your body to adjust. Likewise, turn off the AC about 20–30 minutes before leaving to reduce the shock from temperature changes.

• Regular maintenance: Clean the filters and service the AC periodically to prevent mold and bacteria buildup. A well-maintained system cools more efficiently and lasts longer.

• Ensure ventilation: Open windows occasionally to allow fresh air circulation, preventing the room from becoming too dry or stuffy.

• Healthy lifestyle habits: Stay hydrated, eat plenty of fruits and vegetables, and maintain a balanced diet to strengthen your immune system and reduce the risk of catching a cold from prolonged AC exposure.

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Final Thoughts

Using an air conditioner wisely can improve your quality of life, sleep, and overall health. The key is balance: avoid setting the temperature too high or too low, and take advantage of modern energy-saving features. The ideal nighttime setting for most people is around 26°C with sleep mode enabled, rather than 28–29°C as commonly believed.

By following these recommendations, you’ll enjoy restful, comfortable sleep while keeping your electricity bills under control and protecting your long-term health.