HVACDirect.com Equipment Guide

How to Read an Air Conditioner Model Number

The model number on an outdoor air conditioner can help identify its nominal cooling capacity, product family, efficiency tier, electrical characteristics, refrigerant generation, and factory revision. Use this guide to understand common model-number patterns before comparing replacement equipment.

Find the outdoor unit model number
Estimate cooling capacity and tonnage
Identify the product and refrigerant family

Use the outdoor unit model number, not the serial number. The model number identifies the equipment family and configuration. The serial number generally identifies the individual unit and manufacturing date. Do not order a replacement from model-number decoding alone. A qualified HVAC professional should verify the cooling load, refrigerant, voltage, indoor coil or air-handler match, metering device, line set, ductwork, and AHRI-rated system combination.

First, Find the Outdoor Unit Data Plate

Turn off the disconnect

Shut off electrical power before inspecting or cleaning around the outdoor unit. Do not remove an electrical access panel.

Look on the cabinet exterior

The rating plate is commonly attached near the refrigerant-line connections or electrical service panel. Labels can fade, so photograph the entire plate in good light.

Record the complete model

Keep every letter, number, dash, and suffix. Also record the serial number, refrigerant, factory charge, voltage, minimum circuit ampacity, and maximum fuse or breaker size.

Find the Cooling Capacity in the Model Number

Most residential split-system air conditioners contain a two- or three-digit capacity group representing thousands of BTU per hour. The group may appear near the middle or end of the model number.

Common code	Nominal capacity	Nominal tonnage
`018` or `18`	18,000 BTU/h	1.5 tons
`024` or `24`	24,000 BTU/h	2 tons
`030` or `30`	30,000 BTU/h	2.5 tons
`036` or `36`	36,000 BTU/h	3 tons
`042` or `42`	42,000 BTU/h	3.5 tons
`048` or `48`	48,000 BTU/h	4 tons
`060` or `60`	60,000 BTU/h	5 tons

Quick formula: divide the capacity code by 12 to estimate nominal tons. For example, 036 ÷ 12 = 3 tons. Some manufacturers use nearby numbers such as 017, 019, 041, 047, or 059. These still represent the manufacturer’s nominal 1.5-, 3.5-, 4-, or 5-ton size class.

Matching the old tonnage is only a starting point. The existing system may have been oversized or undersized, and changes to insulation, windows, ductwork, additions, or climate conditions can affect the correct replacement capacity. A Manual J load calculation is the preferred sizing method.

Shop Air Conditioners by Tonnage

Select the tonnage you found in your outdoor unit's model number to view air conditioner condensers with the same nominal capacity.

Current air conditioner size Choose the size identified using the model-number guide above.

Select a Tonnage

Air Conditioner Model Numbers by Brand

Most homeowners using this guide will be identifying an older condenser, so each brand combines older patterns with newer families. Start with the example that most closely resembles the beginning of your model number, then verify the complete number against its rating plate or manufacturer literature.

Goodman & Amana

Older examples: CKL36-1, GSX130361, ASX140361

Newer families: GSXN3, GSXN4, GSXS6, GLXS3B

G / A commonly identifies Goodman or Amana.
36 or 036 identifies the nominal 36,000 BTU/h, 3-ton size in the examples.
13 or 14 in older family names commonly indicated the nominal SEER product tier under the rating system used at that time.
GSXN identifies a Goodman R-410A air-conditioner family.
GLXS3B identifies a newer Goodman R-32 air-conditioner family. Full examples use capacity groups such as 18, 24, 30, 36, 42, 48, and 60.

Daikin

Common examples: DX13SA0361, DX6VSS3610AA

D identifies Daikin in the current nomenclature.
X identifies an R-410A air conditioner in the DX6VS nomenclature; related R-32 families use different current prefixes.
6 identifies the nominal SEER2 band for the DX6VS product family.
V identifies variable-speed compressor operation.
S identifies the side-discharge communicating feature set.
36 identifies the nominal 3-ton capacity, and 1 identifies 208/230-volt, single-phase, 60-hertz electrical service in the current example.

Carrier, Bryant & Payne

Older Carrier examples: 38CKC036, 24ABB336A003

Newer Carrier families: 24SCA5, 26SCA5, 26VNA1

24 has traditionally identified a Carrier residential air-conditioner family. Older Carrier condensers can also begin with 38.
36 or 036 identifies the nominal 3-ton capacity in the examples.
24SCA5 is an R-410A Comfort-family example from the SEER2 generation.
Newer 26-series Carrier air conditioners use Puron Advance, Carrier’s name for R-454B.
Bryant and Payne use related platforms but different family prefixes. Decode the exact number against the correct brand literature.

ICP Brands

Brands include: Heil, Tempstar, Comfortmaker, Day & Night, Arcoaire and KeepRite

Example families: CA5036QKA4, N4A5S36

ICP has used multiple brand-specific and shared family prefixes across generations.
36 identifies the nominal 3-ton size in these examples.
N4A5S is a current-style single-stage R-410A air-conditioner family used by ICP brands such as Heil.
The remaining suffixes can identify voltage, cabinet, sales region, factory options, and engineering revision.
Because the same platform can appear under several brand names, use the brand shown on the rating plate when searching for literature.

Lennox & Allied Air

Older examples: HS29-036-1P, 13ACD-036-230, ML14XC1-036

Newer example: ML14KC1-036-230A01

ML identifies the Lennox Merit product tier.
14 identifies the nominal 14.0-to-14.9 SEER2 family in the newer example.
K identifies R-454B refrigerant; older X-series examples are associated with the previous R-410A generation.
C identifies an air-conditioner condenser, and 1 identifies single-stage compressor operation.
036 is 3 tons; 230 is 208/230-volt, single-phase, 60-hertz service; the ending characters identify revision levels.
Armstrong Air, AirEase and Concord are Allied Air brands and use different family prefixes.

Trane & American Standard

Older examples: TTR036C100A, 4TTR6036B1

Newer R-454B example: 5TTR7036A1000A

TTR / 4TTR appears in older Trane split-system air-conditioner families.
5TTR appears in newer Trane R-454B air-conditioner families.
036 identifies the nominal 3-ton size.
Digits surrounding the capacity identify the product series or efficiency family.
Ending characters identify electrical characteristics, cabinet or design sequence, and factory revision. American Standard uses related equipment with different prefixes.

Rheem & Ruud

Older examples: RAKA-036JAZ, RA1436AJ1NA

Newer examples: RA14AZ36AJ1NA, RA14AY36AJ1NA

R / U commonly identifies Rheem or Ruud.
A identifies an air-conditioner family in these examples.
14 identifies the efficiency family, while 36 identifies the nominal 3-ton capacity.
J commonly identifies 208/230-volt, single-phase, 60-hertz service in these model families.
Current Y-suffix Endeavor families use R-454B; corresponding Z-suffix families are from the R-410A generation.
Longer ending groups can identify controls, protection packages, factory options, and revision levels.

York / Johnson Controls Brands

Older examples: H1RA036S06D, YCJF36S41S1

Related brands: York, Coleman, Luxaire, Champion, Evcon and Guardian

York and related Johnson Controls brands have used different prefixes across product generations and sales channels.
036 or 36 identifies the nominal 3-ton size in the examples.
Other positions can identify air conditioner versus heat pump, efficiency family, voltage, compressor stages, sound package, factory options, and revision.
Use the full brand and model from the rating plate because similar Johnson Controls equipment can carry different brand-specific prefixes.

Nortek Global HVAC Brands

Older example: JS4BD-036K

Brands have included: Maytag, Frigidaire, Gibson, Broan, NuTone, Intertherm and Miller

Many older products are still described as Nordyne equipment even though the current manufacturer name is Nortek Global HVAC.
JS4BD identifies the condenser product family in the example.
036 identifies the nominal 3-ton size.
The final letter identifies an electrical or design option within that family.
Manufactured-home and residential split-system products can use different nomenclature, so verify the exact brand and equipment type.

Bosch

Common outdoor family: BOVA

Many Bosch residential outdoor units sold for whole-home cooling are inverter heat pumps rather than cooling-only condensers.
BOVA model numbers identify Bosch inverter outdoor heat-pump families that provide both cooling and heating.
Capacity groups commonly include 24, 36, 48, or 60, but some Bosch inverter models cover a capacity range rather than one fixed nominal output.
Verify whether the rating plate says air conditioner or heat pump before using a cooling-only replacement workflow.

Refrigerant Generations Matter

The model number may help identify the product generation, but the refrigerant must always be confirmed on the outdoor unit’s rating plate. Refrigerants and components are not interchangeable.

Refrigerant	Where it is commonly found	Replacement consideration
`R-22`	Many older systems manufactured before the R-410A transition	New R-22 equipment is no longer the normal replacement path. A complete matched-system replacement is often required.
`R-410A`	Most residential split systems from the previous generation	Indoor and outdoor components still must be an approved match. Do not assume a new low-GWP outdoor unit can be connected to an existing R-410A coil.
`R-454B`	Newer Carrier, Lennox, Trane, Rheem and other low-GWP product families	A2L-compatible indoor equipment, refrigerant detection or mitigation provisions, controls, and installation practices may be required.
`R-32`	Newer Goodman, Amana, Daikin and other low-GWP product families	Requires equipment specifically designed and listed for R-32, along with the correct A2L installation provisions.

Air Conditioner Terms to Know

BTU/h: British thermal units of cooling capacity per hour.
Ton: A nominal cooling-capacity unit equal to 12,000 BTU/h.
SEER2: A seasonal cooling-efficiency rating under the current test procedure.
EER2: A cooling-efficiency rating at specified operating conditions.
Condenser: The cooling-only outdoor section of a split air-conditioning system.
Heat pump: An outdoor unit that provides cooling and can reverse operation to provide heating.
Single-stage: A compressor that normally operates at one cooling capacity.
Two-stage / variable: Compressors that can operate at multiple or modulating capacity levels.
Matched system: An approved outdoor unit, indoor coil or air handler, metering device, and blower combination.
AHRI rating: Certified performance for a specific combination of indoor and outdoor equipment.
MCA: Minimum circuit ampacity used when sizing supply conductors.
MOCP: Maximum overcurrent protection, such as the maximum fuse or breaker size.

Need Help Identifying Your Current Air Conditioner?

Have a clear photo of the complete outdoor-unit rating plate ready. An HVACDirect.com equipment specialist can help identify the capacity and product family before you compare replacement systems.

Call 1-888-670-6382