How old is my Carrier furnace or AC?

By Dana Whitlock. Updated October 2026. Official format.

Carrier writes the week before the year, which is backward from most brands. The first two digits of the serial are the week of manufacture and the next two are the year. So 2111Q76606 comes from week 21 of 2011, late May.

Carrier's own service manuals label these positions 'Week of Manufacture' and 'Year of Manufacture', so this is an Official format. One gap remains. No unit built in 2020 or later has turned up with an independently dated label. The rule has held for every older unit checked and nothing suggests a change, so read a 2020s result as very likely rather than proven.

Where to find the label on a Carrier furnace

Carrier puts the rating plate (Carrier calls it the nameplate) on one side of the outdoor unit's cabinet. A CPSC recall notice for Carrier outdoor units points owners to the same spot. On a Carrier gas furnace, the plate is inside the blower or burner compartment door. Set the thermostat to off and turn off the furnace's service switch before lifting that door, then read the plate with a flashlight without reaching inside. Some Carrier plates also print a line reading 'Date of Manufacture' with a month and year. If yours has it, you can skip the decoding.

How to read the code

A modern Carrier serial has ten characters: two digits, two digits, one letter, five digits. Read it as WW YY, plant letter, sequence. Carrier's manual uses 0196E00001 to show the layout: week 01, year 1996, plant E, unit 00001. The plant letter tells you the factory (the 24-25-2SM manual lists E for Collierville, Tennessee and X for Monterrey, Mexico) but nothing about age. The week runs 01 to 52 or 53, so a serial whose first pair is above 53 is not this format. To turn a week into a month, divide by about 4.3: week 05 is early February, week 21 is late May, week 40 is early October.

Real serials in this code

When the format changed

This week-and-year layout reaches back to the mid-1980s. Third-party guides give start dates ranging from 1980 to the late 1980s, and the oldest real unit in the published record is a furnace that inspectors dated to 1986 from serial 2386V00518. Serials from before the mid-1980s used other layouts and are not decoded here. Two years can look alike only if you lose track of the century: a 96 is 1996, never 2096. For 2020s units, the best evidence so far is a dealer listing for a new rooftop unit with serial 3623P02576 marked 'built 2023', which fits the rule but does not say how the year was set. If you need certainty for a recent unit, enter the serial in Carrier's warranty lookup.

Who makes Carrier

Carrier builds Carrier, Bryant and Payne equipment. Bryant's website footer reads 'A Carrier Company', and Payne's site now says Payne has become WeatherMaker by Carrier. Bryant and Payne serials follow the same week-then-year pattern, so this page's reading works on those brands too. Carrier residential systems are sold and installed through independent dealers across the US.

How sure is this?

Official format. Carrier publishes how its serial numbers encode the date. We tested the carrier rules against 17 serials, 7 of them with a date known from a recall notice, a printed label date or the maker. None decoded to a wrong year; codes whose year mark repeats show every possible reading. Always confirm with Carrier's serial lookup before you spend money on the answer.

Quick notes

• Read the first pair as a week. Week 11 is mid-March, nowhere near November.
• Look for a printed 'Date of Manufacture' line before you decode anything.
• The plant letter in position five is a factory code, so ignore it when working out age.
• A Carrier furnace and condenser that decode years apart point to a partial replacement. Ask about it before paying for a matched repair.