How to read a Carrier or Bryant serial number
Carrier’s brands share one serial format: four digits, a letter, then four or five digits[1][2][3].
- Digits 1–2: the week of the year it was built (01–52).
- Digits 3–4: the year.
- The letter: the plant. The final digits are the unit number.
40 06 A 17330 → week 40, 2006 → early October 2006
The week is easy to misread as a month. 0519E28045 is week 5 of 2019, which is late January or early February, not May [2].
Which brands use this format
Carrier, Bryant, Payne and Day & Night. Choose “Carrier / Bryant” for any of them. Lennox serials look similar but read differently (see the Lennox page).
Worked examples
| Serial | How it reads | Made | Example from |
|---|---|---|---|
4006A17330 | 40 = week 40 of the year; 06 = year ’06PickHVAC shows a data plate with this pattern dated Oct 2006. | Week 40 of 2006 (around October) | Building Intelligence Center |
0519E28045 | 05 = week 5 of the year; 19 = year ’19 | Week 5 of 2019 (around February) | PickHVAC |
2111Q76606 | 21 = week 21 of the year; 11 = year ’11 | Week 21 of 2011 (around May) | PickHVAC |
3608A17330 | 36 = week 36 of the year; 08 = year ’08Source text says "36th week of 2006… September 2008"; digits say 2008. | Week 36 of 2008 (around September) | PickHVAC |
One source describes 3608A17330 as “the 36th week of 2006” in one sentence and September 2008 in the next[2]. The digits say 2008, so the decoder gives week 36 of 2008.
How far back this format goes
The Building Intelligence Center says Carrier has used week + year exclusively since 1980 [1]; an older inspector’s chart says “since 1990?” [3]. The decoder accepts years from 1980. The disagreement only matters for 1980s units, and no two-digit year can be confused either way. Serials from before 1980 used other layouts that the sources don’t agree on, so they aren’t decoded.
Where to find the serial number
On the rating plate on the outdoor unit’s cabinet, or inside the furnace’s access door (power off first).
Common questions
How do I look up my Carrier serial number?
Enter it above. The first two digits are the week and the next two the year it was built.
Does Carrier’s own website tell me the age?
Carrier’s site handles warranty and registration lookups. This page just reads the date code in the serial number.
How old is my Bryant furnace?
Bryant uses Carrier’s code: digits 1–2 are the week and 3–4 the year.
Not affiliated with Carrier, Bryant, Payne or Day & Night. Brand names are used only to say which serials this decoder reads.
Sources
- Building Intelligence Center: Carrier HVAC AgeUsed for: Week + year first (4 digits, letter, 5 digits).
- PickHVAC: Carrier HVAC Age: Serial Number BreakdownUsed for: Week + year first (4 digits, letter, 5 digits).
- Honest Home Inspections, LLC (hosted by InspectAPedia): How to determine Water Heater and Furnace Age (PDF, last updated 2009-01-06)Used for: Week + year first (4 digits, letter, 5 digits).