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Carrier family

How old is my Carrier furnace or AC?

Enter the serial number from the label. The date comes from Carrier's documented serial rules, not a guess.

Look for “Serial No.” or “S/N” on the label. Spaces and dashes are fine.

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Since at least 1988, Carrier-built equipment has used a 10-character serial: the first two digits are the production week, the next two are the year, then a factory letter and a five-digit sequence.

The same rules apply to Bryant and Payne and Day & Night furnace, AC and heat pumps.

By equipment type

Where to find the serial number

Furnaces: open the upper blower-compartment door; the rating plate is on the inside wall or the door itself. Many newer plates also print a date of manufacture.

Outdoor AC and heat pump units: the plate is on the side of the cabinet, usually next to the electrical access panel.

Questions

What does 4006A17330 mean?
40 is the week and 06 the year: the 40th week of 2006, around early October. That unit's plate also reads 'Date of manufacture Oct 2006'.
Do Bryant and Payne use the same format?
Yes. Bryant, Payne and Day & Night are Carrier brands and share the same serial-number convention.
Why isn't my older Carrier serial decoded?
Before about 1988 Carrier used several letter-based formats, and the available references disagree about them. We'd rather not guess.

Bryant, Payne, Day & Night

Sources

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.