Determining Unit Age
Knowing a unit's age is the first step in any assessment. It provides critical context for its condition, efficiency, and remaining lifespan. An average commercial unit lasts 18-22 years, with some making it to 25 years or beyond.
Serial Number Decoder
Enter the serial number to automatically detect the brand and age. This tool uses the common formats listed below.
Estimated Date:
Logic:
How to Find the Serial Number
The serial number is printed on the unit’s data plate. This is a silver or white sticker, typically found on the exterior of the unit. If it's faded or damaged, check for a second sticker on the inside of the electrical panel door.
Decoding Serial Numbers by Manufacturer
Once you have the serial number, you can decode it to find the manufacturing date. Here are the common formats for major brands:
Carrier / Bryant
Carrier is the parent company of Bryant, and they often share similar serial number formats.
Most Common Format (Post-2000s)
The first four digits represent the week and year. Format is WWYY...
Example: 3521A12345 means the 35th week of 2021.
Older Format
The third and fourth digits represent the year. Format is ##YY...
Example: A401B54321 means the year 2001.
Trane / American Standard
These brands are part of the same company and use identical formats.
Format 1 (2010 - Present)
First two digits are the year, next two are the week. Format is YYWW...
Example: 1832A5B789 means the 32nd week of 2018.
Format 2 (2002 - 2009)
First digit is the year, next two are the week. Format is YWW...
Example: 721A5B789 means the 21st week of 2007.
Format 3 (1983 - 2001)
The first letter corresponds to the year (e.g., 'G' = 1992).
York
Modern Format (Oct 2004 - Present)
The second and fourth characters represent the year. Format is X#X#...
Example: W1D8123456 means the year 2018 (from the '1' and '8').
Older Format (Pre-Oct 2004)
The third letter corresponds to the year. This system repeated, so context is key.
Example: WDHP875237 could mean 1978 or 1999.
ICP (International Comfort Products)
Includes brands like Heil, Tempstar, and Comfortmaker.
The first letter is the factory, the next four digits are the year and week. Format is LYYWW...
Example: E133512345 means the 35th week of 2013.
Mitsubishi
The first digit is the last digit of the year. You must use context (unit condition, ANSI dates) to determine the decade.
Example: 8A123456 could be 2018, 2008, or 1998.
Daikin / Goodman
Daikin acquired Goodman, so formats are now identical.
The first two digits are the year, the next two are the month. Format is YYMM...
Example: 1907123456 means the 7th month (July) of 2019.
This guide covers the most common conventions but may not apply to all units.