Customer had a security tech up in the attic and he noticed something loose on one of the units a 6ft ladder is needed for access into the attic. Found that the filter door for the 2nd floor system had fallen off. Customer has two air handlers in this attic with electronic air filters. There were spares on top of one of the units so I replaced both air filters size 20x20 and taped up the filter door back to the unit. I recommend to the customer to have a maintenance on all of the units in the home the customer is going to follow up with the office.