Lennox is a premium residential HVAC manufacturer sold through a selective dealer network. Lennox International builds premium residential HVAC sold through a selective dealer network, with Aire-Flo as a value line. Lennox uses its own serial-dating scheme.
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Lennox units use the Lennox serial scheme. Here is what each part of the serial number means, by production era:
| A | January |
| B | February |
| C | March |
| D | April |
| E | May |
| F | June |
| G | July |
| H | August |
| J | September |
| K | October |
| L | November |
| M | December |
A Lennox model number is usually built as [product series] · [cooling capacity in thousands of BTU] · [efficiency/SEER] · [voltage/phase] · [refrigerant/revision]. The capacity code is the most reliable part: divide it by 12 for the nominal tonnage — for example 036 = 3 tons, 048 = 4 tons. Enter your model number in the tool above to estimate the tonnage automatically.
Typical service life runs about 10–15 years for air conditioners and heat pumps and 15–20 years for furnaces. Most Lennox parts warranties run 5–10 years and often require registration within 60–90 days of installation. Decode the age above, then confirm exact coverage on the manufacturer's portal:
Open the official Lennox warranty portal →
Lennox International builds premium residential HVAC sold through a selective dealer network, with Aire-Flo as a value line. Lennox uses its own serial-dating scheme.
Visit the official Lennox website →
Brands that share the Lennox serial scheme:
Read the manufacture date from the serial number on the unit's data plate. Enter the Lennox serial number in the tool above and it decodes the year (and often the month or week) using Lennox's published serial scheme.
On the metal data/rating plate — usually on the side of the outdoor condenser, the side of the furnace, or inside the blower door. Look for “Serial”, “S/N” or “SER”.
Most manufacturer parts warranties run 5–10 years and often require registration within 60–90 days of install. Use the age from the tool as a guide, then confirm exact coverage on Lennox's official warranty portal (linked in the result).
The model number encodes the product series, the nominal cooling capacity (tonnage), and usually efficiency, voltage and refrigerant. Enter it above to estimate the tonnage; exact positions vary by product line.
Need a hand, a second opinion, or service on your Lennox unit in the Ottawa area? Cardinal HVAC can help.
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