The Effects of Mold in the Air Conditioner

While air conditioners lower the humidity of the home, which can prevent mold from growing, air conditioners can also cultivate mold inside due to the dust and moisture that collect in the air conditioner.

Mold Prevalence

Unfortunately, mold can lurk in your air conditioner.
Air conditioners can spread mold around through the fan and can hide some of the worst molds, such as black mold. .

Mold grows on any surface with moisture. Air conditioners collect moisture from the air, so these machines create environments where mold can grow. However, mold can grow almost anywhere and air conditioners do not significantly increase the quantity of mold in the home. For example, sinks, showers, toilets and refrigerators also create moisture that can encourage mold growth. All homes contain mold, but most mold does not cause health problems. Only when some strains of mold develop does action need to be taken, as with deadly black mold.


Air conditioners can create stains both on the air conditioner itself and all around the ceiling and walls of the air conditioner. While these stains look unappealing, at least they let homeowners know where the mold is so that they can remove it. You can also identify mold if your home develops a musty smell.

Checking Inside the AC

Some of the deadliest molds are found in hidden places where there is no ventilation and sunlight. Adequate light and air kill many strains of mold. Therefore, homeowners should check inside their air conditioners to look for mold growth and should clean up any growth as soon as possible. Cleaning the air filter is a start, but the air conditioner can also develop mold deep inside. One way to remove mold from an air conditioner is to run the fan only. When looking inside a central air unit, check it for standing water. If water is pooling somewhere in the air conditioner, the device will need repairs and the pooling water will further exacerbate the mold growth. Water created by the air conditioner should drain out through a tube, not sit in the air conditioner.

Health Problems

Mold releases spores that can cause problems in the human respiratory system. The mold can also cause flu-like symptoms, cognitive difficulties and skin irritation. Some spores are also toxic and can cause health problems, even death. Removing mold can be difficult and expensive, especially if the mold lands on a porous surface.

Mold Removal

If your air conditioner causes black mold growth, you will need to purchase protective clothing and a respirator and wear them while removing the black mold. While removing the black mold, run a dehumidifier to inhibit new mold growth. Mold is best killed with bleach, so spray the mold with a lot of bleach before removing it.

About the Author

Charles Pearson has written as a freelancer since 2009. He has a B.S. in literature from Purdue University Calumet and is currently working on his M.A. He has written the ebooks "Karate You Can Teach Your Kids," "Macadamia Growing Handout" and "The Raw Food Diet."