To find the age of a Carrier air conditioner, look at the first four digits of the serial number — they represent the week and year of manufacture. For example, serial number 3216E54321 was made in week 32 (August) of 2016. This same format works for Bryant and Payne units, since all three brands are manufactured by Carrier Global.
Here's the quick formula: digits 1–2 = week number (01–52), digits 3–4 = year (e.g., 22 = 2022). Read on for legacy formats, model number decoding, and what your Carrier's age means for repair vs. replacement decisions.
Where to Find Your Carrier Serial Number
The serial number is on a metal or adhesive data plate:
| Equipment | Location |
|---|---|
| Central AC (condenser) | Upper right side panel or back of the outdoor unit |
| Heat pump | Same as AC — side or back of outdoor unit |
| Furnace | Inside the front cabinet door (remove front panel) |
| Air handler | Side panel or inside access door |
| Package unit | Side panel |
The data plate shows both the model number (starts with numbers like 24ACC, 58MVC, etc.) and serial number (mix of numbers and letters). You need the serial number for age, and the model number for specifications.
Photograph the entire data plate. You'll want both numbers for warranty verification, service calls, and parts ordering. Take the photo on a sunny day or use your phone's flashlight — these plates often fade with age.
Modern Format: 2000s to Present
The vast majority of Carrier, Bryant, and Payne equipment manufactured since the early 2000s uses this format:
Format: WWYY + Plant Code + Sequence
| Position | Characters | Meaning |
|---|---|---|
| 1st–2nd digits | 01–52 | Week of manufacture |
| 3rd–4th digits | 00–26 | Year of manufacture (2000–2026) |
| 5th character | Letter | Manufacturing plant |
| 6th–10th | Digits | Production sequence number |
Decoding Examples
| Serial Number | Week | Year | Manufacture Date |
|---|---|---|---|
| 0122B12345 | Week 01 | 2022 | January 2022 |
| 1318F67890 | Week 13 | 2018 | March/April 2018 |
| 2620A11111 | Week 26 | 2020 | June/July 2020 |
| 3516E54321 | Week 35 | 2016 | August/September 2016 |
| 4825C98765 | Week 48 | 2026 | November/December 2026 |
| 0226D44444 | Week 02 | 2026 | January 2026 |
Week-to-Month Conversion
| Weeks | Approximate Month |
|---|---|
| 01–04 | January |
| 05–08 | February |
| 09–13 | March |
| 14–17 | April |
| 18–22 | May |
| 23–26 | June |
| 27–30 | July |
| 31–35 | August |
| 36–39 | September |
| 40–44 | October |
| 45–48 | November |
| 49–52 | December |
Plant Codes
The 5th character identifies where your unit was manufactured:
| Code | Plant Location |
|---|---|
| A | Syracuse, NY |
| B | Charlotte, NC (formerly Collierville, TN) |
| C | Monterrey, Mexico |
| E | Collierville, TN |
| F | Indianapolis, IN |
| G | Tyler, TX |
| J | McMinnville, TN |
| K | Waller, TX |
Legacy Format: 1970s–1990s
Older Carrier units used a different format with a letter-based year code.
Format: WW + Letter (Year) + Sequence
| Position | Characters | Meaning |
|---|---|---|
| 1st–2nd digits | 01–52 | Week of manufacture |
| 3rd character | Letter | Year of manufacture (see table) |
Year Letter Codes (Cycling Every 20 Years)
| Letter | Year 1 | Year 2 | Year 3 |
|---|---|---|---|
| A | 1971 | 1991 | 2011 |
| B | 1972 | 1992 | 2012 |
| C | 1973 | 1993 | 2013 |
| D | 1974 | 1994 | 2014 |
| E | 1975 | 1995 | 2015 |
| F | 1976 | 1996 | 2016 |
| G | 1977 | 1997 | 2017 |
| H | 1978 | 1998 | 2018 |
| J | 1979 | 1999 | 2019 |
| K | 1980 | 2000 | 2020 |
| L | 1981 | 2001 | 2021 |
| M | 1982 | 2002 | 2022 |
| N | 1983 | 2003 | 2023 |
| P | 1984 | 2004 | 2024 |
| R | 1985 | 2005 | 2026 |
| S | 1986 | 2006 | 2026 |
| T | 1987 | 2007 | — |
| U | 1988 | 2008 | — |
| V | 1989 | 2009 | — |
| W | 1990 | 2010 | — |
Note: I and O are skipped to avoid confusion with 1 and 0. Q is also skipped.
How to determine the correct decade: Cross-reference the letter year with the model number design era and refrigerant type. Units using R-22 with older model number formats are pre-2010. Units using R-410A with modern model numbers are 2010s+. If still uncertain, the physical design (cabinet style, efficiency rating) helps narrow it down.
Legacy Format Examples
| Serial Number | Week | Year Letter | Possible Years |
|---|---|---|---|
| 12E456789 | Week 12 | E | 1975, 1995, 2015 |
| 35K123456 | Week 35 | K | 1980, 2000, 2020 |
| 48T987654 | Week 48 | T | 1987, 2007 |
Carrier Model Number Decoding
The model number tells you what you have — tonnage, efficiency, and product line:
Common Carrier Model Number Prefixes
| Prefix | Product Type |
|---|---|
| 24A, 24S, 24V | Central air conditioner |
| 25H, 25V | Heat pump |
| 38M, 38A | Ductless mini split |
| 58M, 58S, 59M | Gas furnace |
| 40M, 40R | Air handler |
| 50X | Package unit |
Tonnage From Model Number
Look for a 3-digit number in the model number:
| Code | Tons | BTU/hr |
|---|---|---|
| 018 | 1.5 | 18,000 |
| 024 | 2.0 | 24,000 |
| 030 | 2.5 | 30,000 |
| 036 | 3.0 | 36,000 |
| 042 | 3.5 | 42,000 |
| 048 | 4.0 | 48,000 |
| 060 | 5.0 | 60,000 |
Carrier Product Line Identification
| Model Series | Line | SEER2 Range | Compressor |
|---|---|---|---|
| 24ACC | Comfort | 14.3 | Single-stage |
| 24SCA | Performance | 15–16 | Single-stage |
| 24SPA | Performance | 16–17 | Single-stage |
| 24ACA | Performance | 17 | Two-stage |
| 24ANB | Infinity | 19–21 | Two-stage |
| 24VNA | Infinity | 24+ | Variable-speed |
Full Model Number Example
24ACC636A003:
- 24A = Air conditioner product line
- CC = Comfort series
- 6 = 16 SEER (original rating)
- 36 = 3 tons (36,000 BTU)
- A = First revision
- 003 = Configuration
Carrier Efficiency History by Era
Understanding your Carrier's original efficiency rating helps you assess how much energy you're wasting compared to modern systems:
| Manufacture Era | Typical SEER | Equivalent SEER2 | Refrigerant | Efficiency vs. 2026 Minimum |
|---|---|---|---|---|
| 1980s | 6-8 SEER | ~5.5-7.5 | R-22 | 50-65% less efficient |
| 1990s | 8-10 SEER | ~7.5-9.5 | R-22 | 35-50% less efficient |
| 2000-2005 | 10-13 SEER | ~9.5-12.5 | R-22 | 12-35% less efficient |
| 2006-2014 | 13-16 SEER | ~12.5-15.2 | R-410A | 0-12% less efficient |
| 2015-2022 | 14-21 SEER | ~13.3-20 | R-410A | On par to more efficient |
| 2023-2024 | 14.3-24 SEER2 | 14.3-24 | R-410A | Current standard |
| 2026+ | 14.3-24+ SEER2 | 14.3-24+ | R-454B | Current standard, new refrigerant |
If your Carrier was manufactured before 2006 (serial number year digits 05 or lower), you're running at 10-13 SEER — meaning 15-35% of your cooling energy is wasted compared to even the cheapest modern system. For pre-2000 Carrier units still running, the waste is 35-50%.
Bryant and Payne Serial Numbers
Bryant and Payne use the exact same serial number format as Carrier. They're manufactured in the same Carrier Global factories.
Bryant model number prefixes:
- 113A, 116B = Air conditioner
- 215B, 228B = Heat pump
- 310A, 315A = Furnace
Payne model number prefixes:
- PA13, PA16 = Air conditioner
- PH16 = Heat pump
- PG8M, PG9M = Furnace
The decoding process is identical — same WWYY format, same plant codes, same week-to-month conversion.
What Your Carrier's Age Means
| System Age | Status | Recommendation |
|---|---|---|
| 0–5 years | Under warranty | Routine maintenance only |
| 6–10 years | Late warranty / just expired | Maintain well, budget for eventual replacement |
| 11–15 years | Approaching end of life | Repair if under $500, start planning replacement |
| 16–20 years | End of life | Replace with any major repair |
| 20+ years | Well past expected lifespan | Replace proactively before failure |
Warranty Verification
Carrier's standard warranty (when registered within 90 days of installation):
| Component | Warranty Period |
|---|---|
| Compressor (standard) | 10 years |
| Compressor (Infinity select models) | Lifetime |
| Parts | 10 years |
| Heat exchanger (furnaces) | 20 years or lifetime |
Warranty registration is critical. Unregistered Carrier units receive only a 5-year parts warranty instead of 10 years. If you're buying a home with a Carrier system, ask the seller for the warranty registration documentation. If unregistered, the warranty period is calculated from the manufacture date (from the serial number), not the installation date.
Refrigerant Type by Age
| Manufacture Date | Refrigerant | Status in 2026 |
|---|---|---|
| Before 2010 | R-22 (Freon) | Phased out — $80–$150/lb for remaining stock |
| 2010–2024 | R-410A (Puron) | Current but being phased down |
| 2026+ | R-454B | New standard, low GWP |
If your Carrier uses R-22, seriously consider replacement even if the system is otherwise functional. R-22 is no longer manufactured, and the cost of recharging will only increase.
Real-World Decoding Examples
Home inspection scenario: Jennifer was buying a condo. The listing said "2018 HVAC." She found the Carrier outdoor unit with serial number 2215C78901. Decoded: week 22, 2015. The system was actually 3 years older than advertised — manufactured in May/June 2015, not 2018. This affected her negotiation.
Warranty claim: David's 8-year-old Carrier Infinity had a failed capacitor. Serial number: 1018F12345 = week 10, 2018. Still within the 10-year parts warranty. Carrier covered the $85 capacitor; David paid $150 for the service call labor.
Repair vs. replace: Linda's Carrier needed a new compressor. Serial number: 4509E99999 = week 45, 2009. System age: 17 years. Using the $5,000 rule (17 × $2,200 compressor replacement = $37,400), she replaced the entire system with a new Carrier Performance 24SPA6 for $6,800.
R-22 identification: Mike's Carrier AC was low on refrigerant. Serial number: 3206B55555 = week 32, 2006. A 2006 manufacture date confirmed R-22 refrigerant. The tech quoted $600 for a 4-lb recharge. Mike decided to replace the system instead of paying increasingly expensive R-22 costs.
Key Takeaways:
- Modern Carrier serial numbers: digits 1–2 = week, digits 3–4 = year (WWYY)
- Legacy format uses a letter for the year that cycles every 20 years
- Same format works for Bryant and Payne (all Carrier Global brands)
- Always register your warranty within 90 days — unregistered units get only 5-year coverage
- Pre-2010 Carrier units use R-22 (expensive, phased out) — prioritize replacement
- Systems 15+ years old aren't worth major repairs in most cases