Around the early to mid 1980s, the HVAC cleaning industry was becoming known as an industry of fraud. Many companies advertising that they were HVAC cleaners would enter consumer's homes and never actually clean the HVAC system. Instead, they would spray a glue-like substance into the ducts - a process now referred to as encapsulation. Contaminants would adhere to ductwork, instead of being removed. Legitimate HVAC cleaning companies, employing complete source removal methods, were feeling the effects of these companies' actions - including losing business and respect from the public and media. 

The National Air Duct Cleaners Association (NADCA) was formed in 1989 by a group of enterprising ventilation cleaning contractors who were concerned about the rapid growth and lack of regulation in the industry. At that time, there were no industry standards, no credentialing programs, and no system for education for HVAC cleaners. The founding members of NADCA made it their goal to add professionalism to the industry. Those gathered agreed that the number one goal of the organization should be educating the HVAC cleaning industry, as well as consumers, that source removal was the best method of cleaning. 

NADCA established its headquarters in Washington, DC, and produced the first trade show for HVAC cleaning equipment in 1990 at the first of what would be the Annual Meeting & Exhibition. Today, this annual events brings more than 90 equipment suppliers and 800 HVAC system cleaning professionals together for a three-day trade show. The meeting also features dozens of educational seminars led by industry experts, government agency representatives, scientists, and university researchers. 

As NADCA grew, the need for local educational opportunities became apparent. To assist in managing the growing organization, it was divided into eight regions, and Technical Education Seminars were scheduled for the Fall of 1990 in each region. In the spring of 1999, the Board of Directors voted to include Canada as the 9th region of NADCA. In the Fall of 1999, Toronto, Ontario, Canada, hosted the first Technical Education Seminar outside of the U.S. Today, seminars are held in various cities throughout North America during the month of September.