How old is my Armstrong Air equipment?
Enter the serial number from the label. The date comes from Armstrong Air's documented serial rules, not a guess.
Armstrong Air is an Allied Air brand, and Allied Air describes itself as “A Lennox International, Inc. Company”. Allied’s official warranty procedures document is the main source for Armstrong Air dates. Units made since January 1993 use the Lennox layout (plant, two-digit year, month letter), and units from 1978 to 1992 use an older Allied letter format that we also decode.
By equipment type
Armstrong Air furnace age
Typical life: 15–20 years
Armstrong Air air conditioner age
Typical life: 10–15 years
Armstrong Air heat pump age
Typical life: 10–15 years
Questions
- How do I read a 1978–1992 Armstrong Air serial?
- These serials are nine characters. The 7th is the month letter. The 8th is the year: 8 or 9 for 1978–79, then A to N, skipping I. The 9th is the factory, where Allied lists A as Armstrong, B as Bellevue, Ohio, and C as Columbus, Ohio. On a real Armstrong Air plate, A14019ELA reads E for May and L for 1990.
- Does a model number starting with A7 mean Armstrong Air?
- It means Armstrong Air or AirEase. Allied’s spec sheets read “Brand A = AirEase | Armstrong Air”, and both brand sites list the same A7AC and A7HP models. Either way, the serial rules are the same.
- How do I find the age of my Armstrong Air equipment?
- Enter the serial number from the rating plate above. Armstrong Air uses the Lennox family serial format, which includes the manufacture date.
Same serial format
Sources
- Lennox model and serial nomenclature (archived 2010)
- Allied Air warranty procedures WP20565203 Rev 10 (2015): serial number formats
- Building-Intelligence Center: Lennox HVAC age
- Electrical-Forensics: Air conditioner date codes
Rules last reviewed 2026-09-28. These rules are in Beta while we verify more real-world examples, so results are capped at medium confidence.
Manufacture dates are decoded from manufacturer serial-number conventions and available documentation. Serial formats can change. Verify critical equipment information with the manufacturer when necessary.