You can do simple maintenance to keep it clean and operating in peak condition. Start by replacing the furnace air filters as directed–often, this is once every month or every three. Next, clean your air vents once a month, as they can help you see how much dirty air filters through. If you notice them becoming dirtier, you should have your ducts cleaned. With flexible ducting being more susceptible to tears, you’ll want to hire a pro to do the work for you. 

It isn’t a good idea to never clean your ducts. Most appliances have filters for a reason—to clean the air—and over time, they lose their effectiveness. They may eventually become so clogged that your HVAC system will stop functioning correctly or shut down altogether. Cleaning your air ducts is also a requirement if you want clean air in your house. Thorough cleaning checks are recommended to make sure the air is safe from any toxic or harmful contaminants.

Failing to follow an air duct cleaning schedule can allow dust, allergens, and contaminants to accumulate. This can lead to poor indoor air quality and potential respiratory problems or allergies for occupants. Mold and mildew can develop in the ducts, posing serious health risks and creating unpleasant odors. Debris buildup can also restrict airflow, causing the HVAC system to work harder and reduce its efficiency.

Signs that your air ducts need cleaning include visible dust buildup on or blowing from your vents, dirty vent covers, and signs of mold or mildew near vents or inside the ducts. You might also notice a musty or stale odor when your HVAC system is running. Performance issues like weak or reduced airflow, noisy air ducts, frequently clogged air filters, and abnormally high energy bills are also key indicators. Furthermore, if you notice an increase in allergy symptoms or the presence of rodents or insects in your home, it’s time to call an HVAC professional for an inspection and cleaning to improve your home's air quality and system efficiency.