Performed routine maintenance per energy savings agreement. Technician was unable to find any challenges while servicing equipment today. System is cooling and heating properly with a delta t of 20 degrees. Customer does change their own filters. Tech left (1) 24x24x1 because it was all they had on the truck. Notified customer that if they needed another filter just to let us know. Customer is in the process of selling home. Tech let them know that if they move and stay within our service area, we could switch service to their new location. If not, they can notify us to cancel their monthly draft.