Luxaire is manufactured by York and uses their serial number system. A sequence of four letters followed by a string of six numbers was used until October, 2004. The third letter indicates the year of manufacture but, because the letter series repeated every 21 years, some letters will require you to look at the condition of the system or find the year of any industry standard referenced in the fine print of the data plate to determine which of the two years that used the same letter it is.

A = 1971 or 1992 B = 1972 or 1993 C = 1973 or 1994

D = 1974 or 1995 E = 1975 or 1996 F = 1976 or 1997

G = 1977 or 1998 H = 1978 or 1999 J = 1979 or 2000

K = 1980 or 2001 L = 1981 or 2002 M = 1982 or 2003

N = 1983 or 2004 P = 1984 R = 1985

S = 1986 T = 1987 V - 1988

W = 1989 X = 1990 Y = 1992

So the serial number of a Luxaire furnace shown below, which has a “J” as the third letter was manufactured in with 1979 or 2000. The condition of the unit told us it was 2000.