NADCA: The HVAC Inspection, Maintenance and Restoration Association, otherwise known as the National Air Duct Cleaners Association (NADCA) was formed in 1989 as a non-profit association of companies engaged in the cleaning of HVAC systems. NADCA's mission has expanded to include representation of qualified companies engaged in the inspection, cleaning and restoration of HVAC systems. NADCA standards and certification are specified on a regular basis to ensure HVAC systems are assessed, cleaned, and restored in a safe and efficient manner.