Just wondering so did a google search. For more info
HVAC Duct Cleaning: Scam or Worth It? | Today's Homeowner
Should I Have Ducts Cleaned?
Due to growing concerns about indoor air quality, its easy to convince homeowners that their ducts need cleaning. But unless ducts are really dirty, theres no reason to clean them. The EPA takes a similar stance on the issue, recommending cleaning only if the ducts and HVAC unit are contaminated.
If done properly, duct cleaning doesnt hurt; but its not something that needs to be on your regular home maintenance list. You probably dont need to have your ducts and HVAC system cleaned unless:
Renovation: If your home has been remodeled especially if there was asbestos abatement, lead paint removal, or significant dust your ductwork may need to be cleaned. Ducts should be sealed off during home renovations; but if they werent, dangerous dust and debris may become lodged inside the ductwork.
Animals: If theres evidence of animal infestation or nesting in your ducts or HVAC system, have the animals removed then clean the ductwork and HVAC unit.
Mold: If there is visible mold growth inside the ductwork, the ducts and HVAC system should be cleaned.
Contaminants: If noticeable debris, pet hair, odors, or other contaminants are being released into the room through the ducts after the registers have been cleaned and vacuumed; then the ducts may need to be cleaned.
Illness: If someone in your family is suffering from an unexplained allergy-related illness, and youve taken every other possible step to decontaminate your home, you may want to consider having your ducts cleaned to see if the HVAC system was the culprit.