You can easily identify the nominal size of your Trane Air Conditioner and Heat Pump through checking out the model number. This Trane Model Number is usually the data plate at the side of the condenser in outdoor unit. Then find the lable that provides the info about your Trane AC Tonnage.

### What is AC Tonnage?

Heating and air conditioning capacities are sized in British thermal units (BTU) per hour. One BTU is equal to the heat generated by an one little candle. It’s the volume of heat required to bring up the temperature of one pound of water by one degree.

The word tonnage is used to describe the cooling capacity of an air conditioner. One ton of cooling is the rate of heat transfer needed to freeze 2,000 lbs – or one ton – of water in 24 hours. This is equivalent to 12,000 Btu/hr.

### Why is AC Tonnage Important?

In some cases, bigger size is better. But when it comes to air conditioners, in some cases less is more. You should never simply buy the biggest AC unit possible, or you could end up with an oversized system.

## Where to find Trane AC Tonnage?

You should look for the last two numbers of the first numbers after a cluster of letters at the beginning of the model number. It will be a number divisible by 6 or 12, and represents the nominal BTU of the system in thousands. A ton of air conditioning equals 12,000 BTU, and 36 divided by 12 equals 3, so the data plate below indicates the system is 3 tons.

Trane is the only brand we are familiar with that occasionally lists a two-digit number for the thousands of BTU rating that is not divisible by 6 or 12—but close.

Here’s a rundown of the range you will encounter: 18 = 1.5 tons, 24 = 2 tons, 30 – 2.5 tons, 36 = 3 tons, 42 = 3.5 tons, 48 = 4 tons, and 60 = 5 tons. And this is another one that is 2.5 tons.

In case you are doubting whether you have found the right two numbers, you can double check it by checking for the RLA rating. Its located the same on the data plate. RLA is an acronym for Rated Load Amperage, and is what the maximum amperage should be when the condenser up and running. If you divide the RLA by 6 for older units and 5 or 6 for newer units, you should get a number that approximates the tonnage of the system.