Some people suffer from a summer cold, especially when using an air conditioner. This has led them to believe that an air conditioner is the cause of this cold. In reality, HVAC systems only cool the house. The cold produced by these HVAC systems, on their own, can’t cause cold in humans. However, the cool and dry indoor air created by an air conditioner predisposes you to upper respiratory diseases. It causes dryness in your mucus cavity, irritates the skin, and aggravates your eye membrane. All these make it easy for you to contract cold. However, there must be a cold causing organisms in the air for you to catch a cold. Air conditioners also increase the body stress factor. These stress factors come about when your body moves from one air conditioning mode to another, from heat to cold and heat. This constant body temperature change alters your body’s immunity, leaving you vulnerable to disease attacks. In some cases, your body might be suffering from an allergic reaction that mimics cold. It is typical for allergy sufferers to exhibit cold symptoms that can easily be mistaken for cold. It is common to find allergy-inducing contaminants like pollen, dander, dust, and dirt in your HVAC system’s filters that get blown into your indoor space and may cause allergic reactions. To avoid catching a cold when air conditioning your home in summer, you have to clean your HVAC equipment thoroughly and replace its air filters. You also have to open your home windows to let in the fresh air and expel stale air from your home. Install an air purifier to clean your home’s indoor air.