Furnaces & AC / Rheem

How old is my Rheem HVAC unit?

RheemChange
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Where to find the serial number

Rating label on the outdoor AC cabinet
Close-up of a rating label showing the serial numberLook for “Serial” or “S/N” near the service connections

Rheem serial formats we can read

Dark = year, orange = month or week.

Factory letter + week/year

W291013412

Week 29, 2010 (around July).

Coverage and sources

Supports the leading factory-letter + nine-digits layout only. Other embedded-factory and legacy formats are excluded. Water-heater serial rules are different.

References checked 2026-10-26.

Independent reference tool, unaffiliated with Rheem. Sources & method