Every effort is undertaken to offer you correct and concise information to assist you in determining the age or manufacture date of HVAC equipment. Anytime anyone is dealing with numbers and letters in determining data, mistakes and misinterpretation are bound to happen. For this reason if you find during your research that we may have erred please contact us. In addition perhaps you have come across a brand, model or serial number format that we have not addressed. Email us information or pictures of data/nomenclature plates of the unit and we will attempt to assist you in your determinations. Email
This page was last updated: 26 July 2009
American Standard (2002 to Present)
Date of Manufacture (2002 to Present): The manufacturing date code is the first, second and third digits of the serial number, and represented the Year and Week of manufacture. The following numbers were used to indicate the year of manufacture: 2 = 2002; 3 = 2003; 4 = 2004; 5 = 2005; 6 = 2006; 7 = 2007; 8 = 2008; 9 = 2009. NOTE: Beginning in 1987 the date of manufacture was also often (But not always) stamped on the ID Plate.
For example: 227123456 indicate that the American Standard Unit was manufactured in the 27th week of 2002.
Year of manufacture: 227123456
Week of manufacture: 227123456
American Standard (1983 thru 2001)
Date of Manufacture (1983 thru 2001): The manufacturing date code is the first, second and third digits of the serial number, and represented the Year and Week of manufacture. The following letters were used to indicate the year of manufacture: W = 1983; X = 1984; Y = 1985; A = 1986; B = 1987; C = 1988; D = 1989; E = 1990; F = 1991; G = 1992; H = 1993; “I” was not used; J = 1994; K = 1995; L = 1996; M = 1997; N = 1998; “O” was not used; P = 1999; “Q” was not used; R = 2000; “S”, “T”, “U”, “V” were not used and Z = 2001. NOTE: Beginning in 1987 the date of manufacture was also often (But not always) stamped on the ID Plate.
For example: R394X732G indicate that the American Standard Unit was manufactured in the 39th week of 2000.
Year of manufacture: R394X732G
Week of manufacture: R394X732G
American Standard (1980, 1981, and 1982)
Date of Manufacture (1980, 1981, and 1982): The manufacturing date code is the seventh digit of the serial number, and simply indicated the year of manufacture and not the month. The following letters were used to indicate the year of manufacture: O = 1980; T = 1981; U = 1982.
For example:
123456O indicate that this sample American Standard unit was manufactured in 1980.
123456T indicate that this sample American Standard unit was manufactured in 1981.
123456U indicate that this sample American Standard unit was manufactured in 1982.
American Standard (1971 - 1979)
Date of Manufacture (1971 - 1979): The manufacturing date code is the first and second digits of the serial number, written as Year and Month of manufacture. (To determine month: A = Jan; B = Feb; C = Mar; D = Apr; E = May; F = Jun; G = Jul; H = Aug; I was not used; J = Sep; K = Oct; L = Nov; and M = Dec.)
For example: 2D1234 indicate that this sample American Standard unit was manufactured in April, 1972.
Year of manufacture: 2D1234
Month of manufacture: 2D1234