HVAC Decoder
Carrier Tonnage From Model Number
Where Carrier puts the capacity code, what each code means, and the readings that look like capacity but are not. Read out of 2 documents Carrier publishes itself, named further down with the date each was fetched.
Starting the decoder. The capacity tables below this box are already loaded, so you can read your code off them now.
Nominal capacity from a model number is a nameplate convention, not a measurement. Actual delivered capacity depends on the matched indoor unit, line set, airflow and conditions. Confirm against the data plate's BTU/h rating and the AHRI certificate for the matched system.
Carrier Capacity Codes and Tonnage
24 and 25 families (current lettered series)
Capacity sits at positions 7-8, the two digits after the series letters and the SEER digit, per Carrier's own nomenclature table. Example: 24ABC636A0030.
| Code | Nominal BTU/h | Tons | Code / 12 |
|---|---|---|---|
| 18 | 18,000 | 1.5 | same answer |
| 24 | 24,000 | 2 | same answer |
| 30 | 30,000 | 2.5 | same answer |
| 36 | 36,000 | 3 | same answer |
| 48 | 48,000 | 4 | same answer |
| 60 | 60,000 | 5 | same answer |
Table transcribed from 2016 Nomenclatures: Air Conditioners, Heat Pumps, Fan Coils, Evaporator Coils, 90% Gas Furnaces and 80% Gas Furnaces (2016cac_nomen, 2016), fetched from shareddocs.com on 2026-07-24.
Worked example: Carrier 24ABC636A0030
Capacity code 36 at characters 7-8 of 24ABC636A0030: 36,000 BTU/h, which is 3 tons at 12,000 BTU/h per ton. 2 digit BTU/1000 capacity code; the digit before it is the SEER class in Carrier's lettered series.
- Product family: AC condenser. Leading digits 24 (24 = AC condenser, 25 = heat pump, 58/59 = gas furnace).
- Efficiency: 16 SEER. Digit 6 before the capacity code (3 = 13, 6 = 16, 1 = 21 SEER in the 24ACC6 family per Carrier product data).
- Refrigerant: Not in the model number. Carrier implies refrigerant by series and era (Puron R-410A, Puron Advance R-454B on 2025+ series). Decode it from the manufacture year on the serial, not the model.
What is specific to Carrier
The Carrier documents behind this page
Fetched from carrier.com.pr on 2026-07-24. Covers the POSITION only: its MODEL NUMBER NOMENCLATURE table numbers positions 1-13 over Carrier's own worked example and prints position 6 as SEER and positions 7-8 as Cooling Capacity. It prints no code-to-tonnage table, so no tonnage on this page comes from it.
Fetched from shareddocs.com on 2026-07-24. Covers the code-to-tonnage TABLE itself, for both residential families: the Air Conditioners row (Product Series 24) and the Heat Pumps row (Product Series 25) each print positions 7-8 as Cooling Capacity over the same six-code capacity column, transcribed cell by cell into this generation's capacity receipt. It also independently confirms the position claim above.
Frequently asked questions
How do I find the tonnage of a Carrier unit from the model number?
Read the capacity code: on Carrier it sits at positions 7-8, the two digits after the series letters and the SEER digit, per Carrier's own nomenclature table. On 24ABC636A0030 that code is 36, which is 36,000 BTU/h, or 3 tons, because one ton of cooling is 12,000 BTU/h. Use the OUTDOOR unit's model number for system cooling capacity; the indoor air handler or coil carries its own number. This position comes from Carrier's own Catalog No 24ABC6-8PD, not from a third-party chart.
Does dividing the Carrier capacity code by 12 always work?
On the codes in Carrier's printed table, yes: each one is the nominal BTU/h divided by 1,000, so dividing by 12 gives the tonnage. That is not true of every brand. Trane, Lennox, Goodman and Amana each print codes where dividing by 12 is wrong, so do not carry the shortcut across brands.
Where is the model number on a Carrier unit?
On the rating plate on the side of the outdoor condenser, near the refrigerant line connections, labeled MODEL NO. It is labeled M/N, MODEL or MODEL NO., usually printed directly above or beside the serial number. The model number describes what the unit is, including its capacity. The serial number describes when it was built and carries no capacity information at all.
Which Carrier document is this based on?
Product Data 24ABC6 Comfort 16 Air Conditioner with Puron Refrigerant, 1-1/2 to 5 Nominal Tons (Catalog No 24ABC6-8PD, Edition Date 05/19), fetched from carrier.com.pr on 2026-07-24, which covers the POSITION only: its MODEL NUMBER NOMENCLATURE table numbers positions 1-13 over Carrier's own worked example and prints position 6 as SEER and positions 7-8 as Cooling Capacity. It prints no code-to-tonnage table, so no tonnage on this page comes from it. 2016 Nomenclatures: Air Conditioners, Heat Pumps, Fan Coils, Evaporator Coils, 90% Gas Furnaces and 80% Gas Furnaces (2016cac_nomen, 2016), fetched from shareddocs.com on 2026-07-24, which covers the code-to-tonnage TABLE itself, for both residential families: the Air Conditioners row (Product Series 24) and the Heat Pumps row (Product Series 25) each print positions 7-8 as Cooling Capacity over the same six-code capacity column, transcribed cell by cell into this generation's capacity receipt. It also independently confirms the position claim above. Every capacity value on this page traces to one of those documents, and each is named with the date it was fetched so you can pull it yourself.
Is the decoded tonnage the size I should install?
No. Nominal tonnage is what the unit was built to deliver, not what the building needs, and the old unit may have been oversized or sized before insulation and window changes. Treat it as a starting clue and run a load calculation before matching a replacement. Actual delivered capacity also depends on the matched indoor unit, line set, airflow and conditions.
Related tools
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Got the size? Size the circuit next: nameplate MCA and MOCP to wire, breaker and ground per NEC Article 440.
Other brands with their own manufacturer nomenclature document: Trane tonnage by model number, Lennox tonnage by model number, Goodman tonnage by model number, Amana tonnage by model number.
Got the tonnage? Check it against the actual load.
The old unit's nominal size is a clue, not a load calculation. Oversized systems short-cycle and dehumidify poorly. Run the numbers before you match a replacement.