How to manage your air conditioner at summer's end

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With cooler breezes arriving in the mornings and evenings, air conditioners that have been running almost nonstop throughout the summer are nearing their seasonal break. But if you have already put the remote in a drawer and unplugged the unit, thinking, “See you next year,” hold on. Once you are done with your final cooling session, you should not immediately turn off the air conditioner. Instead, run it in fan mode for a while to thoroughly dry out the inside.

Air conditioners naturally accumulate moisture while cooling. When warm air comes into contact with the cold heat exchanger, water vapor condenses into droplets. It is similar to the way water droplets form on the outside of a glass containing a cold drink.

The problem arises when an air conditioner is left unused for a long period without removing this moisture. The warm, humid environment inside the unit can provide ideal conditions for mold to grow. The Ministry of Environment has also emphasized that proper humidity control and regular ventilation are essential to prevent moisture from accumulating indoors and help prevent mold growth.

If your air conditioner gives off a musty odor when you turn it on after a long break, it may be a sign of contamination inside the unit. Dust buildup combined with moisture can create an environment conducive to mold growth.

Mold is more than just an unpleasant source of odor. According to the Korea Disease Control and Prevention Agency’s National Health Information Portal, mold can cause or worsen allergic diseases. People who are sensitive to mold may experience symptoms of allergic rhinitis, including sneezing, a runny nose and nasal congestion when exposed to it. Mold can also aggravate symptoms in people with asthma.

Proper indoor environmental management is particularly important for people with asthma. The KDCA lists indoor allergens such as dust mites and mold among the factors that can worsen asthma symptoms. Therefore, when an air conditioner will not be used for an extended period, it is advisable to dry the inside thoroughly to prevent moisture from remaining in the unit.

After finishing the last cooling session of the season, it is better to run the air conditioner in fan mode for a while rather than turning it off immediately. Running the fan for about an hour with the windows open can help remove moisture remaining on the heat exchanger and other internal components. Air conditioner manufacturers also recommend thoroughly drying the inside of the unit using the fan or air-purification mode before storing it for an extended period.

If your air conditioner is a newer model, it may have an “automatic drying” function that dries the inside of the unit after it is turned off. If the unit continues blowing air or the outlet does not close immediately after you turn it off, it may not be a malfunction but part of the drying process. Since the functions and operating times vary by model, it is best to check the user manual.

It is also a good idea to clean the filter after it has spent the summer in use. Washable fine-mesh filters should be cleaned of dust and washed under running water, then completely dried in a well-ventilated, shaded area rather than in direct sunlight before reinstalling them. However, some specialized filters, such as deodorizing and dust-collecting filters, may lose their effectiveness if washed with water, so check the user manual first.

Finally, if the air conditioner will not be used for a long period, remove the batteries from the remote control and unplug the power cord. Leaving batteries in the remote for an extended period can cause damage if they leak, while unplugging the unit can reduce unnecessary standby power consumption.

This article from Kormedi.com, Korea’s top health care and medical portal, is translated by a generative AI system and edited by The Korea Times.