Lennox® HVAC Age Checker
Enter your Lennox serial number below to determine the manufacturing year of your HVAC system
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How to Find Your Serial Number
Your Lennox serial number can typically be found on:
- The rating plate on your outdoor condensing unit
- Inside the furnace cabinet door
- On the unit's warranty documentation
Lennox Serial Number Formats
Style 1 (1973-Present)
Example: 1606B13871 or 5899L17212
First 2 digits: Factory Code | Positions 3-4: Year | Position 5: Month (letter)
Style 2 (Prior to 1973)
Example: 724 or 6512
Positions 1-2: Year | Position 3 or 3-4: Month (numeric)