Home / Furnaces and AC units / AirEase
How old is my AirEase furnace or AC?
Type the serial number from the AirEase label to see when it was built. AirEase units are built by Allied Air, a Lennox company, so the serials follow that company's format.
Example
- 414072Running number, not part of the date
- 03Year: 03 = 2003
- 28Week: 28 (around July)
Built Week 28 of 2003 (around July)
23 years, 3 months old
In replacement window. Inside the usual 15 to 25 year lifespan, so replacement could come any time. Worth budgeting for it.
How this was read
- The serial is 10 digits with no letter. On this format the date is at the end.
- Digits 7 and 8, 03, are the year: 2003.
- The last two digits, 28, are the week of the year.
Format: All-digit serial with year and week at the end. Sources: InspectAPedia: how to determine furnace age, with Ducane’s explanation (PDF), InterNACHI forum: Armstrong furnace date code, Building Intelligence Center: Armstrong, Building Intelligence Center: Ducane, Inspector Handbook: Armstrong Air, Lennox model and serial nomenclature (PDF).
Reading a AirEase serial number
AirEase is an Allied Air brand. Newer serials use the Lennox layout. Some older ones are all digits with the year and week at the end.
About AirEase
- Lennox Furnace Company started AirEase in Columbus, Ohio nearly a century ago.
- AirEase units are assembled in Orangeburg, South Carolina. Allied Air is based in West Columbia, South Carolina.
- AirEase is sold through independent wholesale distributors in the US and Canada.
Sources: About AirEase, Lennox International Inc. Form 10-K for 2024
Plant code, year and month letter
Used about 1974 to today. Example: 8499F63244
Armstrong Air, Ducane, AirEase and Concord use the Lennox layout: two plant digits, two year digits, then a month letter (A is January, I is skipped). 8499F means June 1999.
Worked example: 8499F63244 was built June 1999, so it is 27 years, 4 months old as of October 2026.
| Letter | Month |
|---|---|
| A | January |
| B | February |
| C | March |
| D | April |
| E | May |
| F | June |
| G | July |
| H | August |
| J | September |
| K | October |
| L | November |
| M | December |
Sources: InspectAPedia: how to determine furnace age, with Ducane’s explanation (PDF), InterNACHI forum: Armstrong furnace date code, Building Intelligence Center: Armstrong, Building Intelligence Center: Ducane, Inspector Handbook: Armstrong Air, Lennox model and serial nomenclature (PDF)
Armstrong month letter and year letter
Used 1978 to 1992. Example: A25175KKA
Older Armstrong serials end in three letters. The first is the month (A is January, I is skipped), the second is the year (8 is 1978, A is 1980, K is 1989), and the last is the plant. A25175KKA means October 1989.
Worked example: A25175KKA was built October 1989, so it is 37 years old as of October 2026.
| Letter | Month |
|---|---|
| A | January |
| B | February |
| C | March |
| D | April |
| E | May |
| F | June |
| G | July |
| H | August |
| J | September |
| K | October |
| L | November |
| M | December |
| Character | Year |
|---|---|
| 8 | 1978 |
| 9 | 1979 |
| A | 1980 |
| B | 1981 |
| C | 1982 |
| D | 1983 |
| E | 1984 |
| F | 1985 |
| G | 1986 |
| H | 1987 |
| J | 1988 |
| K | 1989 |
| L | 1990 |
| M | 1991 |
| N | 1992 |
Sources: InspectAPedia: how to determine furnace age, with Ducane’s explanation (PDF), InterNACHI forum: Armstrong furnace date code, Building Intelligence Center: Armstrong, Building Intelligence Center: Ducane, Inspector Handbook: Armstrong Air, Lennox model and serial nomenclature (PDF)
All-digit serial with year and week at the end
Used about 1990 to the 2000s. Example: 4140720328
Some Ducane, AirEase and Concord serials are 10 digits with no letter. The last four digits are the year (2 digits) and the week (2 digits). Ducane gives 9933 as the 33rd week of 1999.
Worked example: 4140720328 was built Week 28 of 2003 (around July), so it is 23 years, 3 months old as of October 2026.
Sources: InspectAPedia: how to determine furnace age, with Ducane’s explanation (PDF), InterNACHI forum: Armstrong furnace date code, Building Intelligence Center: Armstrong, Building Intelligence Center: Ducane, Inspector Handbook: Armstrong Air, Lennox model and serial nomenclature (PDF)
AirEase recalls
Recalls from the U.S. Consumer Product Safety Commission that name AirEase. Whether a unit is included depends on its model and build date; the checker above flags matches.
| Year | Recall | Hazard |
|---|---|---|
| 2023 | Armstrong Air and AirEase 96% gas furnaces | A part assembled wrong can make the furnace produce high carbon monoxide. |