While air duct cleaning is often marketed as a way to improve air quality, there are some potential downsides to consider. If not done properly, cleaning can release dust, allergens, and debris into the air, temporarily worsening indoor air quality. Additionally, some companies use harsh chemicals that may leave behind harmful residues. Frequent or unnecessary cleaning can also damage ductwork, leading to costly repairs. In many cases, regular filter changes and proper HVAC maintenance provide better results without the risks. Always choose a reputable service provider to avoid ineffective or even harmful cleaning practices.