How old is my AirEase furnace or air conditioner?

By Dana Whitlock. Updated October 2026. Widely documented.

AirEase hides the month in a single letter. On most AirEase furnaces and air conditioners still running, the ten-character serial puts the year in characters three and four and the month letter fifth. A serial shaped like 1606B13871 points to February 2006.

The brand has gone through several label styles. The tool reads the current one plus the nine-character style used from about 1978 to 1992. A couple of older layouts, including one that encodes the day, get skipped. The evidence behind them is too thin to trust.

Where to find the label on a AirEase furnace

AirEase furnaces and air handlers have the rating plate inside the cabinet behind the access door; turn the unit off before opening it. On condensers and heat pumps, the plate is on the outside of the cabinet near the electrical panel. In attic installs, bring a flashlight and photograph the plate rather than leaning into the cabinet. Write down the model too, since AirEase model numbers help a dealer match parts to the right generation.

How to read the code

Ten-character AirEase: two digits for plant, two for year, month letter, five-digit sequence. Month letters skip I: A to H cover January to August, then J, K, L and M finish the year. Nine-character AirEase: a letter, five digits, the month letter in seventh place, a year code in eighth place, and a closing letter. That year code goes 8 for 1978, 9 for 1979, then A for 1980 up to N for 1992 with I skipped. One published example of this older type is C89274AAC.

Real serials in this code

When the format changed

Reference charts show two more AirEase styles: a day-month-year code like 15A67JA098 and an all-numeric one. The tool won't decode either, because not enough public evidence ties them to real dates. For a plate in one of those styles, look for a printed manufacture date, the installer's invoice, or a permit on file. The nine-character table comes from guidance posted on InterNACHI that lumps Armstrong, AirEase, Concord and Magic-Pak together. Read old results as good estimates.

Who makes AirEase

AirEase is an Allied Air Enterprises brand, and Allied Air is a Lennox International company. Lennox's 1999 filing listed Air-Ease among the brands it sells through distributors to local dealers. AirEase shares factories and its serial format with Armstrong Air, Ducane and Concord. AirEase's website handles registration and links to a warranty information lookup.

How sure is this?

Widely documented. AirEase doesn't publish this code; it comes from recall notices, service literature and inspector references. We tested the lennox allied rules against 14 serials, 7 of them with a date known from a recall notice, a printed label date or the maker. None decoded to a wrong year; codes whose year mark repeats show every possible reading. Always confirm with AirEase's warranty page before you spend money on the answer.

Quick notes

• Register new AirEase equipment within 60 days of installation, or within 60 days of closing on a newly built home.
• Without registration, coverage defaults to a 5-year parts and 20-year heat exchanger limited warranty.
• If your AirEase serial has a letter in the third position, it is likely one of the older styles the tool skips.
• Decode the furnace and the outdoor unit separately. A replaced condenser shows up as a much newer year sitting next to an old furnace.