A.O. Smith® Water Heater Age

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How to determine the date of production/manufacture or age of A.O. Smith® Water Heater(s) from the serial number.

As of 2019, A.O. Smith® will have celebrated 145 years in business, and continues to be one of the world's leading manufacturers of commercial and residential water heaters and boilers. A.O. Smith® provides a comprehensive product line featuring many of the best known brands in the industry. The company began in 1874 making metal parts for baby carriages and bicycles. From this early beginning, A.O. Smith® grew into an integral part of the automobile revolution when it developed a new lightweight steel car frame in 1899. This car frame was eventually supplied to the likes of Cadillac, Oldsmobile, and Ford. Over the years, A.O. Smith®  continued its devotion to technology and innovation as it developed or improved on several manufacturing processes including production line automation, an improved method of welding, and the process of fusing glass to steel which led to glass-lined beer kegs, brewery tanks, and residential water heaters.

A.O. Smith® remains a popular water heater brand for residential and commercial applications. After several company acquisitions (GSW, American, State, Takagi, Lochinvar), their line of water heaters includes the brand names: GSW, John Wood, Whirlpool, U.S. Craftmaster, American, State, Reliance, Kenmore, Takagi, and Lochinvar.

Serial number styles/formats found are:

→Style 1a: 1210A002243
→Style 1b: S1318 F000046
→Style 1c: 1836111786352

→Style 2: AF04A093001

→Style 3: CG03-1495366-S29

→Style 4: E07A135491


Style 1a: 1210A002243
Style 1b: S1318 F000046
Style 1c:  1836111786352

The Date of manufacture is coded in the 1st four numerical digits of the serial number.

The first set of numerical digits represent the year

The second set of digits represent the week of manufacture.



Style 2: AF04A093001

Serial number begins with two letters. This style has been discontinued.


Style 3: GG03-1495366-S29

Similar to style 2 above. This style has been discontinued.


Style 4: E07A135491

This style discontinued somewhere between 2008-2010

A.O. Smith® History¹

  • 1874 - Machine shop started as Charles J. Smith - Machinist (name later changed to C.J. Smith and Sons)
  • 1889 - Introduces concept of forming steel tubing from sheet metal and enters the bicycle manufacturing industry, eventually becoming the largest bicycle parts manufacturer in the world
  • 1899 - Arthur O. Smith (son of Charles) develops the worlds first pressed steel automobile frame
  • 1902 - Company receives first order of auto frames from Peerless Car Company - closely followed by orders from Cadillac, Packard, and Oldsmobile
  • 1904 - Arthur O. Smith incorporates the A.O. Smith Company
  • 1906 - Henry Ford orders 10,000 steel auto frames, leading the company to develop the first mass production process for assembling frames
  • 1914 - Develops Smith Motor Wheel, a gas powered device for bicycles
  • 1918 - Develops coated welding rod which influenced the development of arc welding as a mass production method
  • 1921 - Reveals the world's first fully automated frame assembly plant , dubbed "the Mechanical Marvel"
  • 1936 - Patents the process of glass lining a water heater tank
  • 1939 - Begins producing residential water heaters
  • 1942 - Produces bomb casings, aircraft propellers, nose frames for the B25 bomber, and landing gear for the war effort
  • 1948 - Acquires Burkay Company of Toledo, OH and enters market for coil-type commercial water heaters
  • 1949 - Introduces "Harvestor" glass fused to steel silo for dairy and livestock operations
  • 1953 - Glascote Products, Inc. becomes a subsidiary of A.O. Smith® expanding its vessel manufacturing capabilities
  • 1961 - Opens commercial water heater and boiler plant in Ontario, Canada
  • 1967 - Begins making fiberglass body panels for Corvette Stingray
  • 1972 - Water heater division opens first European operation in the Netherlands
  • 1982 - Company produces 100 millionth passenger car frame
  • 1995 - A.O. Smith® enters China market with three joint ventures
  • 1997 - Sells automotive division and exits the auto industry after 98 years
  • 2001 - A.O. Smith® acquires State Industries, Inc.
  • 2006 - Acquires Canadian GSW, Inc. and American Water Heater Company. The addition covers American, Whirlpool, GSW, and John Woods brands
  • 2010 - Acquires Takagi's North American operations as a joint venture to market and manufacture tankless water heaters in North America
  • 2011 - Acquires Lochinvar Corporation, leading manufacturer of high efficiency water heaters and boilers
  • 2016 - A.O. Smith® enters water treatment market through acquisition of Aquasana
  • 2017 - Expands North American water treatment presence through acquisition of Hague Quality Water

¹History excerpts derived from research at https://www.aosmith.com/About/History/