I have spent the last 2 years and thousands of dollars trying to resolve an odor issue in my home. The first thought is that is coming from the crawlspace. Professionals also say that you have to control the airflow. I have had the ducts cleaned and aerosesled, Attic top plates and penetrations sealed, total house weather stripped, register boots sealed, soil gas mitigation system in crawl space also attached to garage, crawlspace encapsulation and dehumidifier with Hi-Lo for the HVAC. I am still getting odor that comes through the vents when the HVAC runs. I am at my wit's end with this. Not sure what to do next. Is it possible that the odor is lodged somewhere in the HVAC unit that needs to be cleaned out? I was considering some deodorization of the wood / porous things in the crawlspace. Help!