Air conditioners have their purpose, particularly if you live somewhere hot where it gets 90-100 degrees or hotter in the summer. They work by pulling the humidity out of the room, cooling it, then releasing cold air back out of the air conditioner. Unfortunately, it also dries the air out in the room which can make dry eyes, dry skin, and dehydration worse.
Air conditioners also irritate the mucus membranes and can make allergies, respiratory illnesses, and asthma worse. Additionally, if they are not well maintained, then air conditioners can blow dust, debris, and mold spores into the air of your home. Cleaning your air conditioner regularly and only using it when necessary reduces some of these risks.