Lennox HVAC Age Lookup by Serial Number
Decode your Lennox serial number to find the manufacturing date, system age, and maintenance recommendations. Free and instant. No account needed.
Finding Your Lennox Serial Number
Check these four spots on your HVAC system
Common Locations
What to Look For
- White or metallic manufacturer sticker
- Labeled "Serial No." or "S/N"
- Typically 8–12 characters long
- Usually near the model number
Can't find it? Try the electrical access panel on the front of the outdoor unit or inside the air handler cabinet.
Serial Number Examples
Don't worry if yours looks different — each brand has multiple formats and our system can decode most variations.
About Lennox HVAC Systems
Lennox was started in 1895 by Dave Lennox, who built the first riveted steel furnace in America, which was a genuine engineering step forward at a time when cast iron dominated the market. The company is still headquartered in Texas and manufactures a significant portion of its equipment domestically. The residential line covers furnaces, air conditioners, heat pumps, air handlers, and indoor air quality equipment. Lennox sells through dealers rather than home improvement stores, which usually means better installation quality. Serial numbers encode the manufacture date as week and year in the first four digits. A unit built in week 52 of 1996 starts with 5296.
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