Kenmore water heater age by serial number
The serial number is on the model and serial plate on the tank jacket. Kenmore water heaters with a model number starting 153 were built by State: since 2008 the serial starts with the year and the week, and before that with a letter for the month.
Decode a Kenmore serial number
How to read a Kenmore serial number
Kenmore has used 2 serial formats. Find the one that matches the shape of your serial.
Year and week, first four digits
Skip a leading letter if there is one. The first two digits are the year and the next two are the week of that year.
Shape: four digits, then a letter and six digits, or nine more digits. Some serials carry one extra letter in front.
1210A002243 reads as week 10 of 2012 (around March).
Month letter, then two-digit year
The first letter is the month, A for January through M for December with the letter I left out. The two digits after it are the year.
Shape: one letter, two digits, then a letter and six digits or six to eight digits.
E07A135491 reads as May 2007.
Month letter
- A January
- B February
- C March
- D April
- E May
- F June
- G July
- H August
- J September
- K October
- L November
- M December
State and Reliance used this layout for decades. A. O. Smith-branded heaters carry it only from July 2004, when the leading factory letter was dropped, to 2007.
Where to find the serial number
The model and serial plate is on the outside of the tank jacket.
If the serial number does not decode
- Sears did not build water heaters. Kenmore models whose number starts with 153 were built by State Industries, later part of A. O. Smith, and follow the State formats on this page. Some Kenmore heaters came from other makers, and those serials are not covered here.
- The small print at the bottom of the plate names the company that built the heater. Store brands changed makers over the years.
What the age tells you
| Equipment | Typical service life |
|---|---|
| Tank water heater | 10 to 15 years |
| Tankless water heater | about 20 years |
About Kenmore
Kenmore is a store brand created by Sears and owned by Transformco since 2019. Sears never built the products itself. Each Kenmore product was made by another manufacturer, and the serial number follows that manufacturer’s format.
Brands that share this serial system: State, A. O. Smith, Reliance.
Questions and answers
Which characters in a Kenmore serial number show the date?
Skip a leading letter if there is one. The first two digits are the year and the next two are the week of that year. This applies to units built since 2008.
Why does my Kenmore serial number look different?
Kenmore has used 2 serial formats: year and week, first four digits (built since 2008); month letter, then two-digit year (built until 2007). The decoder tries each one.
Who makes Kenmore water heaters?
Sears did not build water heaters. Kenmore models whose number starts with 153 were built by State Industries, later part of A. O. Smith, and follow the State formats on this page. Some Kenmore heaters came from other makers, and those serials are not covered here.
Sources
- A. O. Smith Canada: frequently asked questions, reading the serial number (manufacturer): https://www.hotwatercanada.ca/faqs/
- A. O. Smith International: manufacturing date of a device (manufacturer): https://aosmithinternational.com/manufacturing-date-device/
- CPSC recall 19-029: A. O. Smith ultra-low NOx water heaters, serial ranges by build date (US Consumer Product Safety Commission): https://www.cpsc.gov/Recalls/2019/A-O-Smith-Recalls-Ultra-Low-NOx-Water-Heaters-Due-to-Fire-Hazard
- Building Intelligence Center: A. O. Smith water heater age (independent reference): https://www.building-center.org/a-o-smith-water-heater-age/
- CPSC recall: A. O. Smith, State, Reliance, Maytag and Apollo water heaters, serial prefixes by month (US Consumer Product Safety Commission): https://www.cpsc.gov/Recalls/2005/cpsc-ao-smith-recall-of-water-heaters
- CPSC recall: A. O. Smith gas water heaters, serial ranges for units sold November 2007 to January 2008 (US Consumer Product Safety Commission): https://www.cpsc.gov/Recalls/2008/ao-smith-recalls-gas-water-heaters-due-to-fire-and-carbon-monoxide-hazards
- Building Intelligence Center: State water heater age (independent reference): https://www.building-center.org/state-water-heater-age/
- Appliance411: Sears and Kenmore model prefixes by manufacturer (independent reference): http://www.appliance411.com/parts/sears.shtml
- Building Intelligence Center: Kenmore water heater age (independent reference): https://www.building-center.org/kenmore-water-heater-age/
Formats last checked against these sources on October 5, 2026. Found a serial that does not fit? Send a correction. How formats are verified: method and sources.