Nasal, sinus, throat, chest, and skin symptoms can be aggravated by very dry air. We recommend a cool mist vaporizer. Fill the tank of the vaporizer with hot tap water or distilled water; use only distilled water in ultrasonic humidifiers. Place the device in a safe location to avoid risk of spilling the hot water; please, direct the mist so that furniture or carpeting will not be soaked. Pour out the remaining water in the morning and let the device air dry during the day. Refill with hot tap water each night. Only use the device in the bedroom at night when the heat is on.