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How Old Is My Lennox Air Conditioner?
Characters 3 and 4 of a Lennox serial number are the year and character 5 is a letter for the month. Type the serial number from your air conditioner's data plate below.
Where the serial number is on a air conditioner
On the outdoor unit (the condenser), look for the data plate on the side panel, often near the electrical box where the power cables go in. The indoor coil or air handler has its own plate with a different serial number.
How to read a Lennox serial number
Characters 3 and 4 of a Lennox serial number are the year and character 5 is a letter for the month.
10 characters, 1974 to today
PP YY M #####
- Characters 1 and 2 are the factory.
- Characters 3 and 4 are the year: 98 means 1998, 10 means 2010.
- Character 5 is the month as a letter.
Example: 5898F06044
Month letters: A = January, B = February, C = March, D = April, E = May, F = June, G = July, H = August, J = September, K = October, L = November, M = December (there is no I).
Units made before 1974 use an older code that we do not decode yet.
How long does a air conditioner last?
Most air conditioners last 12 to 17 years. Yearly servicing, the local climate and how hard it works all move it within that range. Past 12 years, it is worth getting a replacement price before the unit fails, so you aren't forced into a rushed decision.
Air conditioners made before 2010 almost always use R-22 refrigerant, which is no longer produced in the US. If an older unit leaks, replacing it is often cheaper than recharging it.
Questions
How do I find the age of my Lennox air conditioner?
Characters 3 and 4 of a Lennox serial number are the year and character 5 is a letter for the month. You'll find the serial number on the data plate. On the outdoor unit (the condenser), look for the data plate on the side panel, often near the electrical box where the power cables go in. The indoor coil or air handler has its own plate with a different serial number.
How long does a Lennox air conditioner last?
Like most air conditioners, a Lennox typically lasts 12 to 17 years with regular servicing.
Related
How sure are these dates? Checked against official records (recall notices or data plates with printed dates). How we test the decoder.
Keeping an older air conditioner going
- Ac condenser coil cleaner: Dirty outdoor coils make an older unit work harder.
- Furnace air filter: The indoor filter matters for cooling too.
- Smart thermostat: Cuts run time on any system, old or new.