If you were cleaning before they passed the law then I believe you are grandfathered in. Otherwise you have to comply. I'm lucky in my state they only require contractors to register with the State. I can pull the fan, clean the burners, take apart the ductwork to access the evap coil and no license is needed. I would however have to have a gas fitters license to install furnaces and a Freon certification to service Central Air units. So when we clean an Air duct system. We clean supplys, returns, fans coils burners, fog with benefect and install new filter.