Room temperature can significantly impact sleep quality, especially if it is too hot or cold. While the optimal air conditioning (AC) temperature for sleeping is 65°F (18.3°C), this may vary slightly among individuals.

A suitable AC temperature and other sleep hygiene habits can make it easier to fall asleep and improve sleep quality. This is especially important during the summer months and for people living in warm climates.

This article covers the best AC temperature for sleeping, how temperature affects sleep, and tips to improve sleep.

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Sleeping in a room with the air conditioner set to an appropriate temperature is important for quality sleep. The ideal AC temperature for sleeping is around 65°F (18.3°C). However, this may differ between individuals, who might find their ideal AC temperature lies between 60 and 67°F (15.6 and 19.4°C).

A cool room helps people get quality sleep, in part due to its effect on circadian rhythms, which control bodily processes, such as core body temperature and the sleep-wake cycle. Setting the AC to a suitable temperature can help regulate core body temperature, which decreases slightly a few hours before bedtime and during the night.

A lower body temperature lets the body know it is time to go to bed and fall asleep. A room that is too cold or warm can interfere with these signals, making it more difficult to fall asleep and sleep deeply. Additionally, people with an out-of-balance circadian rhythm — when it is out of alignment with the day-night cycle — may experience more interruptions during sleep and find it harder to get enough sleep.

It is safe to sleep with the AC on if a person keeps their AC unit clean and ensures it undergoes regular maintenance. These units, including their filters and ducts, generally require cleaning twice a year. This helps prevent the accumulation and dispersion of airborne contaminants such as dust mites, volatile organic compounds, and pet dander. Additional irritants may include mold, pollen, and bacteria.

Sleeping with the AC on helps prevent heat-related conditions, such as dehydration, heatstroke, and heat exhaustion.

Typical AC filters will not purify the air, though they can prevent dust and particles from entering the unit. There are specialized filters that can help purify the air by removing irritants such as pollen, microbes, and bacteria.

Using an AC system also allows a person to close the windows and sleep with an air purifier, which also promotes cleaner air. This is particularly helpful for people with asthma, allergies, or respiratory issues.

A room that is too hot or too cold can make it difficult for people to sleep well, and it can cause common issues such as restlessness, difficulty falling asleep, and waking up in the night. A room that is too hot also causes more sleep disturbance than one that is too cold.

Furthermore, a room that is too warm can cause discomfort, restlessness, and sweating, which may lead to dehydration. Research suggests sleeping in an overheated room may also increase wakefulness, making it hard to fall asleep, and decrease sleep efficiency, leading to fatigue. High temperatures may also reduce appetite and increase heart and respiratory rates.

A person’s core body temperature drops before bedtime as the core distributes heat and blood to the extremities, which causes warmer hands and feet. A core body temperature that is too warm and therefore not sending heat to the extremities may reduce the amount of restorative slow-wave sleep and sleep quality a person receives. A high core body temperature can also decrease sleep efficiency and cause frequent waking.

In contrast, sleeping in a room that is too cold may make it harder to fall asleep and sleep deeply. A 2021 animal study suggests that, compared with a control temperature of 73.4°F (23°C), temperatures of 59°F (15°C) and 64.4°F (18°C) have links to poor sleep quality, increased interruptions during sleep, and reduced delta wave activity associated with deep sleep. The lower temperatures also increased blood pressure and heart rate.

To improve sleep quality, people can follow a regular sleep routine and practice good sleep hygiene.

Individuals can help improve their sleep by:

  • sticking to a consistent sleep routine and schedule, even on weekends
  • limiting daytime naps to 30 minutes
  • getting regular exercise
  • using a white noise machine or earplugs if noise is a concern
  • using an eye mask to block out light
  • using comfortable, natural fiber bedding and cleaning it regularly
  • investing in a high quality mattress and pillow set
  • sleeping in the nude or wearing natural fiber pajamas
  • taking a warm shower or bath 1–2 hours before bed
  • eating a light, easy-to-digest evening meal, as large meals can overstimulate digestion
  • performing breathing exercises, meditation, or relaxing stretches
  • using scented candles, room sprays, or essential oils before bed to signal to the brain that it is bedtime
  • consuming drinks that promote sleep, such as herbal tea, cherry juice, or milk
  • avoiding or reducing the intake of alcohol, caffeine, and sugary drinks, especially in the afternoon and evening
  • turning off electronics a few hours before bedtime and keeping devices out of the bedroom
  • dimming or turning off lights before bed and using only night lights during the night
  • using blackout curtains to filter out street lights
  • allowing natural light to come into the room 30–60 minutes before waking

Read more tips on how to sleep better.

Getting sufficient quality sleep is important for health and overall well-being.

With this in mind, it is vital to set the AC temperature to a comfortable and appropriate level for a person to fall asleep easily and sleep deeply.

For most people, a bedroom temperature of around 65°F (18.3° C) is ideal. This temperature may make it easier to fall asleep and improve sleep efficiency.