I investigated the customer’s concerns about an odor in the upstairs area. The smell is confirmed to be Dirty Sox Syndrome but it is more noticeable on the upstairs. This is because the upstairs zone has fewer ducts and more air flow. I presented the airscubber digital book and offered biocide treatment on the evaporator coil. I informed the customer that it is not a guaranteed long term fix of the issue especially if only the treatment is done.