Found no issue with upstairs thermostat. Thermostat is operating equipment however equipment was very low almost empty on R 22 refrigerant. Not cooling. Performed maintenance on both upstairs and downstairs systems. Replaced both 14x20x1 filters. Downstairs system is cooling normally. Back to upstairs, spoke with customer about significance of upstairs system and its low refrigerant condition. Customer wishes at this time to add refrigerant to system so that it can cool but she would like an estimate on system replacement. Customer was informed that should she replace this upstairs system we would discount the amount she spent on refrigerant. Added 5 lb 407c refrigerant to upstairs system.