You should replace your humidifier pad at the end of the furnace season. This way you won’t breathe mold or bacteria all summer long during the cooling season. If you forget, make sure you replace it before the next heating season.
Usually you can get a Clean & Check done on your furnace or air conditioner for around $89 to $119. Most HVAC contractors will clean your humidifier and replace your humidifier pad for $35 to $45 with a Clean & Check.
Stay Healthy and Breathe Safe