Trane serial number lookup: age of a furnace, AC or heat pump

The serial number is on a label on the back of the outdoor unit or on the side panel of the furnace. On a Trane built since 2010, the first two digits of the serial are the year and the next two are the week.

Decode a Trane serial number

Look for “Serial”, “Serial No.” or “S/N” on the rating plate. It is not the model number. What you type stays in your browser.

How to read a Trane serial number

Trane has used 5 serial formats. Find the one that matches the shape of your serial.

Built since 2010

Two-digit year, then week

The first two digits are the year and the next two are the week.

Shape: ten characters starting with four digits.

13year03week13596L
Example: serial 130313596L reads as week 3 of 2013 (around January).

Trane counts weeks on its own fiscal calendar, so the month shown for a week is approximate.

Built 2002 to 2009

One-digit year, then week

The first digit is the last digit of the year, 2 for 2002 through 9 for 2009. The next two digits are the week.

Shape: nine characters starting with three digits.

9year15week31S41F
Example: serial 91531S41F reads as week 15 of 2009 (around April).

The rating plate behind the example also prints “MFR DATE 4/2009”, which matches week 15. Trane counts weeks on its own fiscal calendar, so the month shown for a week is approximate.

Built 1983 to 2001

Year letter, then week

The first letter is the year. The letters are not in alphabetical order, so use the chart. The two digits after the letter are the week.

Shape: nine characters: a letter, two digits, then six more characters.

Ryear17week42DWBF
Example: serial R1742DWBF reads as week 17 of 2000 (around April).

Year letter

  • W 1983
  • X 1984
  • Y 1985
  • S 1986
  • B 1987
  • C 1988
  • D 1989
  • E 1990
  • F 1991
  • G 1992
  • H 1993
  • J 1994
  • K 1995
  • L 1996
  • M 1997
  • N 1998
  • P 1999
  • R 2000
  • Z 2001

The rating plate behind the example also prints “MFR DATE 04/2000”, which matches week 17.

Built 1980 to 1982

Year letter at the end

The letter in the seventh position is the year. The serial gives no month or week.

Shape: six digits followed by one letter.

123456Tyear
Example: serial 123456T reads as 1981.

Year letter

  • A 1980
  • O 1980
  • B 1981
  • T 1981
  • C 1982
  • U 1982

One reference swaps T and U. Five others agree that T is 1981 and U is 1982.

Built 1971 to 1979

Year digit, then month letter

The first digit is the last digit of the year, 1 for 1971 through 9 for 1979. The letter after it is the month, A for January through M for December with the letter I left out.

Shape: a digit, a letter, a dash and four digits.

2yearDmonth1234
Example: serial 2D-1234 reads as April 1972.

Month letter

  • A January
  • B February
  • C March
  • D April
  • E May
  • F June
  • G July
  • H August
  • J September
  • K October
  • L November
  • M December

Where to find the serial number

On an air conditioner or heat pump the serial label is on the top right of the back of the outdoor unit. On a packaged unit it is on the rear panel.

On a furnace the label is on the right or left side panel. On an air handler or an indoor coil it is on the front panel.

If the serial number does not decode

  • Most rating plates print the manufacture date in a field marked “MFR DATE”. When it is there, read it directly.
  • Count the characters to tell the recent layouts apart: ten characters with a two-digit year since 2010, nine characters with a one-digit year from 2002 to 2009.
  • Trane and American Standard equipment has at times been built by other manufacturers. A unit built by another company follows that company’s serial format.
  • The manufacturer can confirm the date from the serial: Trane registration, warranty or serial lookup.

What the age tells you

EquipmentTypical service life
Furnace15 to 22 years
Central air conditioner10 to 21 years
Heat pump15 to 16 years

What size is it?

The model number on the same rating plate gives the size: the tonnage of an air conditioner or heat pump, or the heating input of a furnace. Trane model number tonnage shows where the digits sit and reads them for you.

About Trane

Trane was owned by American Standard Companies from 1984 and by Ingersoll Rand from 2008. The company has been called Trane Technologies since 2020. Trane and American Standard heating and cooling equipment shares one serial system, which changed in 2002 and again in 2010.

Brands that share this serial system: American Standard.

Questions and answers

Which characters in a Trane serial number show the date?

The first two digits are the year and the next two are the week. This applies to units built since 2010.

Why does my Trane serial number look different?

Trane has used 5 serial formats: two-digit year, then week (built since 2010); one-digit year, then week (built 2002 to 2009); year letter, then week (built 1983 to 2001); year letter at the end (built 1980 to 1982); year digit, then month letter (built 1971 to 1979). The decoder tries each one.

The decoder shows more than one possible year. Which one is right?

Part of the Trane date code repeats, so the serial alone fits more than one year. A manufacture date printed on the rating plate, the print date of the owner’s manual or the installation record settles it. For equipment that is still running, the more recent year is usually the right one.

Why are the year letters out of order?

From 1983 to 2001 the first letter of the serial was the year, but the letters were not assigned alphabetically: W is 1983, X 1984, Y 1985, S 1986, then B for 1987 through P for 1999, R for 2000 and Z for 2001. The chart on this page lists every letter.

Sources

Formats last checked against these sources on October 5, 2026. Found a serial that does not fit? Send a correction. How formats are verified: method and sources.