Mold Issue Forcing Redo of HVAC

[Patrick McKenna]

I was just alerted to a potential mold issue at a rental house I have. From the pictures I have seen thus far, the mold seems to be pretty pervasive throughout all of the vents, making me think this may force me to have to redo the entire HVAC system (as opposed to just getting it cleaned and sanitized). I have had a mold specialist out to the property to take an initial look. The actual HVAC unit itself is old (20+ yrs) and the vents / ducts are only somewhat newer, so I knew this was going to have to take place sooner or later. Just wondering if anyone has any experience with mold remediation and HVAC overhauls in single family rental properties that are occupied by tenants?

Thanks.