Lennox uses a three-digit code after the series (e.g. -036). Paste your model number for an instant decode.
Always confirm against the data plate's rated capacity line — model ranges occasionally reuse digits for non-capacity codes, and the plate is authoritative.
| Capacity code | BTU/hr | Tons |
|---|---|---|
| 09 | 9,000 | 0.75 |
| 12 | 12,000 | 1.0 |
| 18 | 18,000 | 1.5 |
| 24 | 24,000 | 2.0 |
| 30 | 30,000 | 2.5 |
| 36 | 36,000 | 3.0 |
| 42 | 42,000 | 3.5 |
| 48 | 48,000 | 4.0 |
| 60 | 60,000 | 5.0 |
Amana American Standard Blue Star Bryant Carrier Daikin Goodman Heil Hitachi LG Lloyd O General Panasonic Payne Rheem Ruud Samsung Trane Voltas Whirlpool York
On the data plate — a metal or foil sticker on the side or back of the outdoor unit (or behind the front panel on indoor split units). Use the model number, not the serial number, which encodes the manufacture date rather than capacity.
Lennox uses a three-digit code after the series (e.g. -036). Divide the BTU code by 12 to get tons.
Paste the model number from the outdoor unit's data plate into the decoder above — it applies Lennox's nomenclature automatically. Example: XC16-036 = 3.0 tons.
Lennox is the one major US brand that does not use tidy multiples of 12. It ships non-standard capacity codes — 019, 026, 031, 041, 047, 049 — alongside the familiar 018/024/030/036/042/048/060. The decoder maps both sets (e.g. 041 → 3.0 tons).
Current models read as a tier prefix + SEER + system + capacity, e.g. ML14XC1-036. The tier letters are ML (Merit, entry), EL (Elite, mid) and SL/XC (Signature, premium). XC/AC marks an air conditioner; XP/HP a heat pump. The trailing three digits are the capacity code.
Older units use a SEER-then-family layout such as 13ACD-036 or HS26-041. Here HS26 is the family and 041 is the capacity code (→ 3.0 tons) — note that the 26 is not the size.
The decoder above applies this nomenclature automatically. Capacity codes are nominal — always confirm against the rated-capacity line on the unit’s data plate.
Capacity decoding on this page follows Lennox’s published model-number nomenclature. To confirm a unit’s actual rated capacity and efficiency, cross-check the authoritative references below.
Tonnage is derived from nominal cooling capacity: 1 ton of refrigeration = 12,000 BTU/hr.
Model-number conventions and standards evolve, and manufacturers occasionally reuse digits for non-capacity codes — the rated-capacity line on the unit’s data plate is always authoritative. Figures here are for identification and planning, not a substitute for a professional load calculation.
Different brand? Back to the full 22-brand decoder. Sizing a replacement? Check what your space really needs with the AC tonnage calculator first — the old unit may have been mis-sized.