To determine the AC tonnage from the model number, you will need to locate the manufacturer’s information plate on the air conditioner. This plate will typically be located on the outdoor unit or inside the indoor unit. This data tag displayed important information about the system, including the tonnage.
The size of an AC unit refers to its cooling capacity and is measured in tons. One ton of cooling is equivalent to the amount of energy required to melt one ton of ice in 24 hours. Therefore, the higher the tonnage, the greater the cooling capacity of the AC unit.
Go outside to the condensing unit and look for a data plate mounted to the side. Up near the top of the label, you’ll see the model number (M/N) and serial number (S/N). The model number is where you can find the size of AC you’re looking for.
Not all air conditioning companies do this, but most will give you a 2 or 3 digit section in AC model number that says how many thousands of BTU/hour your air conditioner can cooling of your house.
If the model number on your air conditioning system lists the tons, no more calculation is needed as you now finally found the right AC tonnage of your cooling system.
Divide the BTUs on the label by 12,000. You need to use this number as the divisor because there are 12,000 BTUs per ton. The result of this calculation will be the tons of your central air conditioning system.
For example, assume that your system is labeled as having 60,000 BTUs. Dividing 60,000 by 12,000 will give you 5 tons. This is the most accurate method on determining the size of your central air conditioning system when your label does not indicate the tons on it directly.
If you don’t want to do the math, here are the numbers you’re looking for and their corresponding tonnage:
- 18 = 1.5 tons
- 24 = 2 tons
- 30 = 2.5 tons
- 36 = 3 tons
- 42 = 3.5 tons
- 48 = 4 tons
- 60 = 5 tons
How to read AC model number?
The tonnage of an AC unit can typically be determined from the model number by looking for a number that is divisible by 12. For example, if the model number is ABC12345, and the number 36 appears in the middle of the model number (e.g., ABC36 12345), then the AC unit is likely a 3-ton unit, since 36 is divisible by 12.
The 3 digits in the model number tell you the nominal capacity in thousands of BTU/hr. Since each 12,000 BTU/hr is equivalent to 1 ton of air conditioner capacity, it’s easy to figure out how many tons of nominal capacity your AC has.
Finding AC tonnage from model number is very important and detrimental to the proper operational status of an air conditioning system. Suppose your system does not have the BTU or the tons of information detailed on the data tag; you need to read the model number to identify its size. We have a complete list of how to read AC model numbers from every manufacturer.
