Complete 1 system furnace repair and preventative maintenance check. Find a 5-year-old Lennox heating system. Change filter 20x25x1, check safety and operations, find system operating with in manufacturer spec. No concern at this time. Find an evaporator coil for the cooling system badly rusted. Suggest in-line water protection for the system in the attic. Suggest an air purifier system to improve air quality and prevent molding.