Tenant turns AC WAY down! What can I do?

[Robert Lasko]

I have a tenant who's awesome!  She takes care of the place, pays on time, and doesn't cause any issues.  She is a dream tenant!  

My only complaint is that she runs the AC at 68 during the day and turns it to 64 at night.  She lives in a 3 story townhouse and says she needs cold air to sleep and for health reasons. 

Because the Thermostat is turned so low, a lot of condensation is forming on the ductwork inbetween the first floor ceiling and the second floor floor.  So much condensation that it's dripping through the ceiling!  The ducts are not insulated because WV code says that since it's between the floor Joyce's, it's considered controlled air space and doesn't need to be insulated.  How can I solve this problem with the tenant so I don't have to cut the entire cieling out and insulate the duct work to fix the condensation?