A duct condition assessment documents accessible HVAC components before cleaning is proposed. Ask to see what was observed, where it was found and what the recommended work would address. Dust at a grille alone is not a complete picture of the system, and an assessment is not a medical diagnosis.
Ordinary dust at a grille
Ask for context before buying system cleaning. EPA does not recommend routine cleaning without a reason.
Moisture or suspected growth
Ask how the condition will be evaluated. The cause may require attention beyond surface cleaning.
Debris after renovation
Describe the work and affected rooms. Agree on the components and contamination being addressed.
Agree on the scope
A symptom is a starting point. Ask what the assessment will establish and which findings would change the proposed work.
Useful references
EPA · when to consider duct cleaning ↗General guidance. Confirm the scope for your property.