HVAC systems components over time may become contaminated with particles of dust, pollen or other debris. If moisture is present, the potential for microbiological growth (e.g., mold) is increased and spores from such growth may be released into the home's living space. Some of these contaminants may cause allergic reactions or other symptoms in people if they are exposed to them. Furnace cleaning helps to reduce the potential for these toxins and removes soot from entering your home and helps your furnace run more efficiently.