AC Model Number Guide: Identify Your Unit Quickly

When your air conditioner isn’t working properly, it helps to know what type you have, though most people don’t, especially if it’s been a while since purchase or service. Cousin's Air, Inc.’s NATE-certified technicians can help identify your AC using the model number. While there isn’t a universal decoder (each manufacturer uses different codes) your model number reveals important details like capacity, tonnage, speed type, voltage, refrigerant, and brand.

Use this guide to decode your AC model number quickly, with step-by-step examples and brand-specific insights.

What AC Model Numbers Can Tell You

AC model numbers typically contain information about:

• Unit Size & Capacity – Measured in tons or BTU.
• Efficiency Ratings – SEER/SEER2 codes indicate energy efficiency.
• Refrigerant Type – Common types include R‑22 or R‑410A.
• Manufacture Year – Helps determine age and warranty eligibility.
• Voltage & Phase – For proper electrical compatibility.

Tip: Always check both the model and serial number on your unit’s label. They often work together to confirm your system’s specifications.

How to Find Your AC Model Number

1. Locate the nameplate: Usually found on the outdoor condenser unit.
2. Check your indoor unit: Some systems list model numbers on the air handler.
3. Read carefully: Look for labels that include letters and numbers; avoid confusing serial numbers with model numbers.

How Do I Read My AC Model Number?

Let's look at a Trane brand air conditioner as an example.

Capacity: Trane has used a number of different methods for encoding capacity information in the model number. It is commonly found in the first three digits – sometimes as BTUs and sometimes as tons.

Example:

• SPCC-B504-A = 5.0 ton, or
• TWS748A = 48,000 BTU = 4 ton

Age: For units manufactured up through the 1970’s, the date of manufacture information is found as a number and a letter in the serial number where the number is the single digit year and the letter indicates the month. A=Jan, B=Feb, C=Mar and so on.

Example:

• 1C-xxxx = March 1971

Standard Decoding Patterns by Brand

Here’s a quick reference table showing how common brands format model numbers:

How to Read Your AC Unit’s Age From the Serial Number

When the manufacture date isn’t listed outright on the nameplate, you can often determine when an AC unit was built by decoding its serial number. Most major manufacturers embed week and year or month and year codes in specific parts of that number.

💡 Note: Model numbers identify unit specifications: capacity, size, and series, while serial numbers are where age/manufacture date information is found.

Carrier, Bryant & Payne

• Format: WWYYxxxxxx
• Meaning: First two digits = manufacture week of the year, next two digits = year.
• Example: 3515E23456 → 35th week of 2015 (mid‑August)

Trane & American Standard

• Format: Letter + two digits often represent month and year.
• Month code: Letters A–L indicate January through December.
• Example: R16H… → “R” = April, “16” = 2016 

Tip: This format is typical, but Trane serial decoding can vary by product line and age. Contacting Trane with the full serial can confirm the exact manufacture date if unclear.

Goodman & Amana

• Format: YYMMxxxxxxx
• Meaning: First two digits = year, next two digits = month.
• Example: 1708A98765 → August 2017

Lennox

• Format: Most modern Lennox serials start with four digits, where the first two represent the week and the next two represent the year.
• Example: 1915E12345 → Week 19 of 2015

In some older Lennox units, a letter may indicate the month while numbers indicate the year.

Rheem & Ruud

• Format: Often MMYYxxxxxxx or WWYYxxxxxxx.
• Meaning: First two digits = month or week | Next two digits = year
• Example: 0618A12345 → June 2018

Key Tips for Accurate Age Decoding

Always use the full serial number from the nameplate. Small variations can change the format. 

If a serial number appears too short or too long, or if the date code doesn’t make sense (e.g., month > 12), check the manufacturer’s official decoding tool or customer support. 

Some older units or specialty models (e.g., imported or obsolete brands) may follow unique serial patterns, professional check tools or manufacturer lookup services can help in those cases.

Common Questions About AC Model Numbers

What if my AC model number doesn’t match standard patterns?

Some older units or specialized models may have unique formats. When in doubt, check the manufacturer’s website or consult an HVAC professional.

How do I use this for repair or replacement?

Knowing the exact model number ensures you order compatible parts, schedule proper service, and confirm energy efficiency ratings.

f you still need help decoding your air conditioner’s model or serial number, trust the experts at family-owned Cousin's Air, Inc.. Our NATE-certified technicians have the experience and knowledge to quickly identify your unit’s specifications, including capacity, efficiency, and age. We can also guide you on replacement parts, repairs, or upgrades to ensure your AC is running efficiently all year long.

Call us today or schedule a service online to get personalized assistance and make sure your air conditioner is performing at its best.