How To Determine Ac Tonnage From Model Number Lennox. This designation is the last letter in the unit model number. Tonnage, air flow, kw, etc.
Lennox® air conditioners and heat pumps are available in tonnages ranging from 1.5 to 5 ton capacities. This number can be elusive, as it is not always exactly divisible by 6. The sequence of letters and digits in the lennox model number
For lennox, you should look for the second cluster of digits of the model number.
For example a 1 ton system would have 12,000 btu’s. For example, the “xc21” at the beginning of the model number of the lennox condenser shown below indicates it is rated at 21 seer. This equals the total number of btus you need to adequately cool your space. For example, a unit with 18,000 btus has a tonnage of 1.5.