How old is my A.O. SMITH?

1. Find the rating label. Where to look on each kind of appliance.
2. Take a photo of the whole label, or note the model and serial numbers.
3. Use the lookup below. It is free, and no account is needed. A date is shown only when the available evidence supports it.

A.O. Smith water heater age: year and production week

The numeric year/week water-heater serial format illustrated by A.O. Smith · Sources checked October 12, 2026

A.O. Smith’s July 2024 service guide illustrates a numeric serial in which the first two digits identify the manufacture year and the next two identify the production week. A production week is not a month: 19 means week 19, not month 19.

Read the appliance rating plate and keep the complete model and serial together. This example explains the documented numeric arrangement; it does not establish a rule for every older, lettered or other product-family serial.

Record manufacture and installation dates separately. If the label does not match the documented arrangement, preserve the original characters and ask A.O. Smith to confirm the date rather than rearranging digits to produce an answer.

The model identifies the product family, not the manufacture date of your individual heater. An age result also does not establish warranty coverage or predict remaining service life; check the unit’s warranty information separately.

• A.O. Smith July 2024 service and warranty guide: serial example, page 9
• A.O. Smith official warranty verification

A.O. SMITH appliances

How to find the age, the serial number, typical life and parts for each:

• A.O. SMITH water heater (tank)8–12 yrs
• A.O. SMITH tankless water heater15–20 yrs
• A.O. SMITH boiler15–30 yrs

A. O. Smith makes gas and electric tank water heaters, gas and electric tankless units, hybrid and split-system heat pump water heaters, combi boilers and solar storage tanks, plus commercial water heaters and water treatment products; heat pump water heaters are counted as water heaters here.

A. O. Smith is a Milwaukee company that describes itself as the largest maker and seller of water heaters in North America. It sells residential and commercial water heaters and boilers under its own name and owns many other water heating and water treatment brands, including State, GSW, John Wood and Giant.

Owned by

A. O. Smith Corporation (publicly traded, NYSE: AOS)

Headquarters

Milwaukee, Wisconsin, United States

Founded

1874

Product lines

Adapt (gas tankless), Cyclone (commercial)

Sister brands: State Water Heaters, American Water Heaters, Reliance Water Heaters, Lochinvar, GSW, John Wood, Giant, Takagi, Aquasana.

• 1874: Charles J. Smith opened a machine shop in Milwaukee that grew into A. O. Smith; its early products included bicycle parts.
• 1939: The company began making residential water heaters.
• 2000s: A. O. Smith bought State Industries of Ashland City, Tennessee, and boiler maker Lochinvar.
• 2006: It acquired GSW, a Canadian water heater maker, bringing in the GSW and John Wood brands.
• 2021: It bought Giant Factories of Montreal for about US$192 million.

Every A.O. SMITH check is compared with Health Canada, U.S. CPSC and U.S. NHTSA recall notices.