Performed 4 system one time insoection. Check and tested electrical component,inspect filters , inspected safeties, and humidifiers. Also check charges Upstairs unit is 21 years old for the ac and coil and furnace is newer at 9 years old, no proper gas connection and sediment trap dirty blower, low charge R22, pitted contactor m. And no te flood protections. Has special medical grade filters system. Basement unit has cracked heat exchanger found with inspection camera, single wall flue , no te flood protections failed dual capacitor and pitted contactor. Recommend replacement of system. Also has special medical grade filters that are $400 for a pack of 4. Mai level unit is the main reason custom contacted up. Found failed blower motor and failed blower wheel improper flue vent as well. Outdoor unit has a band dual capacitor. Has 2 16x25x 4 filters. Master level unit is 9 years old as well smallest system located in the attic. Had humidifier removed but on the side. Also has no t