How old is my A.O. Smith tankless water heater?
Serial number age decoder for A.O. Smith tankless water heaters: 1 format era, the decode rule in plain English, transcribed tables, and the official lookup.
Type the serial from the data plate, not the model number. Nothing is sent anywhere; the tables are in this page.
Format example: 1210A002243
- A.O. Smith tankless water heater serial numbers in the 2008 to present format encode the year as digits 1-2 (YY) after optional leading S and the week as digits 3-4 (source: building-center.org).
- Example: serial 1210A002243 decodes to week 10 of 2012.
- A.O. Smith's official lookup at hotwater.com returns warranty status.
Format eras
- 2008 to present VERIFIED
####A######digits 1-2 (YY) after optional leading S
How to read the serial
2008 to present formatVERIFIED
Shape ####A###### · example 1210A002243 / S1318 F000046 / 1836111786352 · confidence high
- Year
- digits 1-2 (YY) after optional leading S
- Week or month
- week = digits 3-4
- Plant
- letter after the 4 date digits (unpublished)
Example: serial 1210A002243 decodes to week 10 of 2012.
Where the data plate is on a tankless water heater
On the side or bottom of the wall-hung cabinet, or inside the front cover on the frame.
General guidance, not brand-specific: the owner's manual or the installer can point to the exact spot. See the data plate guide.
For scale only: the InterNACHI Standard Estimated Life Expectancy Chart for Homes lists Instant (on-demand) Water Heater at 10 years of expected service (nachi.org). That chart is a guideline, not a prediction for your unit.
Open the official A.O. Smith lookup takes serial or reference number; returns warranty status; URL verified live
This site is a reference built from published tables. The manufacturer's own lookup wins whenever the two disagree.
Sources
- https://www.building-center.org/a-o-smith/
- https://www.hotwater.com/support/warranty-verification.htmlofficial
Frequently asked questions
How do I tell the age of a A.O. Smith tankless water heater from the serial number?
In the 2008 to present format the year is digits 1-2 (YY) after optional leading S and the week as digits 3-4. Example: serial 1210A002243 decodes to week 10 of 2012.
Where is the serial number on a A.O. Smith tankless water heater?
On the data plate. On the side or bottom of the wall-hung cabinet, or inside the front cover on the frame.