Some hvac brand also has new code for its new hvac units. For example, York hvac had two different serial numbers for 1971 through 2004 and for 2005 through the present day.
You can’t use information from 2005 to decode 1980 hvac unit, it wouldn’t works. These air conditioner numbers mean a lot. Without the serial and model number, it would be hard to find a replacement part of that central ac unit (I’m not referring to small parts). You could say air conditioner serial and model number is it characteristics or it identities. The Air Conditioner Serial and Model Number Tells Hvac model number tells you: Types of hvac unit, refrigerant types, hvac ton, voltage, compressor series, seer rating, and other thing.