There is no universal list of chemicals that should be applied inside every HVAC system. A product that is suitable for a different surface is not automatically approved for ductwork, and a product name alone does not prove that it is needed or effective for a particular concern.
Questions to ask before any treatment
EPA says an antimicrobial product used in an HVAC system must have a label that specifically includes that use. EPA also advises that the system be inspected, cleaned and/or repaired first, and that label directions be followed. Ask which documented condition the product is intended to address and request the product label before approving an application.
Routine duct cleaning has not been shown to prevent health problems. Correct moisture, pest entry, or damaged material at its source; do not rely on a sanitizer to prevent recurrence or treat a person's symptoms.
Local next steps
In Hampton Roads neighborhoods such as Little Creek, a photo inspection can document an accessible duct concern before service is recommended. If the concern is a pest entry point rather than duct debris, Universal Pest in Virginia Beach serves the region. Compare the tier-specific benefits of the Total Home Health plans.