How to find tonnage of AC Unit

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How to Find the Tonnage of Your AC Unit 
Newport Beach HVAC Services – (949) 603-2536
If you’re trying to figure out what tonnage your AC unit is, you’re not alone. Homeowners in Newport Beach often call us asking:

• “How many tons is my air conditioner?”
  
• “Where do I find AC tonnage on the model number?”
  
• “How many BTUs is my AC?”
  

Your AC’s tonnage is the measurement of its cooling capacity. One ton of cooling = 12,000 BTUs per hour. Knowing your AC size is essential for repairs, replacement, home additions, or solving issues like uneven cooling.
This expert guide explains the fastest ways to find AC tonnage, how to decode model numbers, and what tonnage means for your home.

⭐  The 3 Easiest Ways to Find AC TonnageYou can find your AC tonnage using:
1. The AC Nameplate (Manufacturer Label)Located on the outdoor condenser unit, usually on the side or back. Look for:

• “Tonnage”
  
• “Cooling Capacity”
  
• BTU/hr”
  

2. Decoder Numbers in the AC Model NumberMost air conditioners hide the tonnage in the model number as:
18 = 1.5 tons
24 = 2 tons
30 = 2.5 tons
36 = 3 tons
42 = 3.5 tons
48 = 4 tons
60 = 5 tons
3. Online tonnage lookup using brand/modelIf numbers aren’t clear, you can search your model number on the manufacturer’s website.

1. Find the AC Tonnage on the Nameplate (Most Accurate)Every outdoor condenser has a data tag that lists:

• model number
  
• serial number
  
• voltage
  
• refrigerant type
  
• cooling capacity (BTU/hr)
  

Look for a number around:

• 18,000 BTU (1.5 tons)
  
• 24,000 BTU (2 tons)
  
• 36,000 BTU (3 tons)
  
• 48,000 BTU (4 tons)
  
• 60,000 BTU (5 tons)
  

How to read BTUs → tons:Tonnage = BTU ÷ 12,000
Example:
36,000 BTU ÷ 12,000 = 3 tons
If the tag is worn off (common in Newport Beach due to salt air), use the model number method below.

2. Decode Tonnage From the Model Number Nearly every HVAC brand—Carrier, Lennox, Trane, Goodman, Rheem, Bryant, York—includes tonnage directly in the model number.
Look for a two-digit number between 18 and 60.
Examples:
Model Number   Tonnage Indicator                                                                                                                                                                    AC SizeGSX14024242 tons
4TTR6036363 tons
13ACXN048484 tons
RA1648AJ1NA484 tons
CA13NA060605 tonsWhy these numbers matter:

• 18 = 18,000 BTUs → 1.5 tons
  
• 24 = 24,000 BTUs → 2 tons
  
• 30 = 30,000 BTUs → 2.5 tons
  
• 36 = 36,000 BTUs → 3 tons
  
• 42 = 42,000 BTUs → 3.5 tons
  
• 48 = 48,000 BTUs → 4 tons
  
• 60 = 60,000 BTUs → 5 tons
  

These numbers are usually located in the middle of the model number, but every brand formats differently.

3. Search the Model Number OnlineIf the label is hard to read:

1. Take a photo of the model number.
   
2. Search “MODEL NUMBER + ‘specifications’”.
   
3. Look for: Cooling Capacity, BTU, or Tonnage.
   

Carrier, Lennox, and Trane have full spec sheets available online.

4. Find Tonnage Through the Indoor Air Handler or FurnaceIf your outdoor label is unreadable, your indoor unit may list the compatible cooling capacity.
Look for:

• “Airflow CFM” (Cubic Feet per Minute)
  
• “Up to X tons cooling capacity”
  

Air handlers sized for:

• 2-ton -> ~800 CFM
  
• 3-ton -> ~1200 CFM
  
• 4-ton -> ~1600 CFM
  
• 5-ton -> ~2000 CFM
  

5. Estimate AC Size by Square Footage If labels are unreadable and model numbers are missing, here’s a rough guide:
Home Size (sq ft)AC Size600–900 sq ft1.5 tons
900–1200 sq ft2 tons
1200–1500 sq ft2.5 tons
1500–1800 sq ft3 tons
1800–2200 sq ft3.5 tons
2200–2600 sq ft4 tons
2600–3200 sq ft5 tonsImportant for Newport Beach:Homes near the beach often require higher tonnage due to humidity and indoor–outdoor temperature differences.

Why AC Tonnage MattersUnderstanding your AC tonnage helps with:
1. Correct ReplacementOversized AC → short cycling & humidity problems
Undersized AC → long run times & warm rooms
2. Repair CostsTechs need tonnage to order:

• capacitors
  
• motors
  
• compressors
  

3. Energy BillsA properly sized system uses less electricity and cools efficiently.
4. Home AdditionsIf you've added a sunroom or expanded square footage, your system may be undersized.

What If You Can’t Find the Tonnage?Salt air in Newport Beach often fades or corrodes equipment labels.
If your label is unreadable and model numbers are missing:
✔ We can measure refrigerant capacity
✔ Check compressor rating
✔ Look up manufacturer data with the serial number
✔ Calculate airflow through the air handler
We can determine tonnage in 5–10 minutes on-site.

Professional Tip: Tonnage Is Not WeightMany homeowners think “ton” means the AC weighs one ton.
It doesn’t.
A "ton" refers to the amount of heat required to melt one ton of ice in 24 hours — a historical measurement that became an HVAC standard.

Need Help Finding Your AC Tonnage? We Can Do It in Minutes.Newport Beach HVAC Services📍 1901 Westcliff Dr, Newport Beach, CA 92660
📞 Call: (949) 603-2536
🌐 www.hvacnewportbeach.com
We provide:

• AC sizing & tonnage verification
  
• AC repair & maintenance
  
• Full system replacements
  
• Coastal HVAC corrosion protection
  
• Free second opinions
  

Same-day service available in Newport Beach, Costa Mesa, Corona del Mar, and surrounding areas.

Frequently Asked Questions on Finding your AC TonnageWhere can I find the AC tonnage on my unit?On the nameplate sticker, typically listed as BTU/hr or hidden in a two-digit model number.
What does 36 mean in a model number?36 = 36,000 BTUs = 3 tons.
Is a 3-ton AC big enough for a 2,000 sq ft home?In many cases yes, but humid coastal homes may require 3.5 tons.
Can AC tonnage affect energy bills?Yes—oversized systems short cycle and waste energy, while undersized units run constantly.