Furnace maintenance and safety inspection. Cleaned and serviced furnace. The furnace is 32 years old and at the end of its lifespan. Tested all mechanical components. Cleaned all sensors. Tested gas valve voltage and inlet/outlet pressures. Tested blower motor amperage. Found the ignitor and flame sensor to be very corroded. The customer agreed to replace both parts. Replaced thermostat batteries for the customer. Replaced the furnace filter that the customer provided. Giving customer estimates for the replacement of both furnace and ac units. The heating system is clean and operating adequately at this time. Performed free plumbing inspections.