Customer has 24 y/o Rheem system that operates for whole house. Furnace located in attic. System was not heating due to very dirty filter preventing proper airflow and causing system to short cycle. Replaced 16x25x1 filter. Noticed during inspection that water protection is poor. Blower wheel cleaning needed. Inducer motor is bad. Ignitor is bad. Duct cleaning needed. Recommend thermostat replacement. Customer stated that system does not cool properly as well. System is R22 based. Informed customer is all findings. Based on our findings today, it might be time to think about getting a brand new system.