The parts that make up the various HVAC units produced by York have an average life span of 10 to 20 years. Certain parts, such as the heat exchanger on the Affinity series of York furnaces, have a lifetime guarantee from the company.
On average, most HVAC units start showing signs of failure after 10 years of operation. Signs of a potential HVAC malfunction are loud noises or strange smells. An aging unit also uses more energy than it should, indicating that it is losing its effectiveness. While older HVAC units can still operate as they deteriorate, it is sometimes more economically efficient to replace them.