Why should you be cleaning your air ducts? Because dirty air ducts could be endangering your health and property. Heating, ventilation, and air conditioning (HVAC) systems have been shown to act as a collection source for a variety of contaminants that have the potential to affect health, such as mold, fungi, bacteria, and very small particles of dust. The HVAC system then blows the containments all over your home or business. These containments are breathed in, land in food and drink, and build up in electronic equipment and machinery.