HVAC systems contain three major components:
1. Supply and return registers/grills;
2. Interior duct surfaces from return and supply ducts; and
3. The Air handler and Coil. All components must be properly cleaned following NADACA source removal procedures.
If a component is not cleaned, it will contaminate the system as soon as the system is turned back on after the cleaning. The average size residential house requires a 2 to 3 person crew 8 hours to properly clean; if a company is doing it faster they aren’t following the NADCA source removal standard.