Lennox Evaporator Coils

Cased, uncased, horizontal and downflow coils

The coil sits on top of, under or beside your furnace, so the cabinet style has to match how the furnace is installed:

• CK40CT and CX35: cased upflow coils.
• C35: upflow coils.
• CK40DT: cased downflow coils.
• CK40HT and CHX35: cased horizontal coils.
• CH23: 10 inch wide horizontal coils built to install with most Lennox horizontal furnaces.
• CK40UT: uncased upflow coils, 13 to 23 inches wide, for a coil that goes inside the plenum.

How to read a Lennox coil model number

Take CK40CT-30/36B-71. The first C means indoor coil, K means R-454B, and 40 is the Quantum coil series. The C after 40 is the cased upflow cabinet (D is downflow, H is horizontal, U is uncased), and T is the factory expansion valve. 30/36 is the 2.5 to 3 ton size. The cabinet letter matches your furnace: A is 14.5 inches, B is 17.5, C is 21 and D is 24.5. The ending 71 means R-454B only, and 01 means the coil ships with an R-410A valve.

CK40 and CHX35 coils use the Lennox Quantum coil, with aluminum tubing and ripple-edged aluminum fins.

Match the refrigerant to your outdoor unit

A replacement coil has to use the same refrigerant as the outdoor unit it connects to. CK40 coils ending in 71 are R-454B only and come with a factory refrigerant detection sensor. The Lennox air conditioners and heat pumps we sell use R-454B. If you are keeping an R-410A outdoor unit, look at the C35, CX35 and CHX35 coils or a CK40 model ending in 01. Lennox sells C35, CX35 and CHX35 coils in the U.S. for repair and replacement only, not for new systems.

Match your coil with AHRI

Your SEER2 rating belongs to the matched system, not to the coil alone. Each AHRI certificate lists one outdoor unit, one coil and, for many systems, the furnace. You can look up a combination in the AHRI Directory, or send us the model numbers from your data plates and we will check it with you.

Shop the rest of the system: Lennox air conditioners, Lennox heat pumps and Lennox furnaces. If you want the outdoor unit and coil already matched, see our Lennox matched systems. No furnace? A Lennox air handler has its own coil and blower.

Warranty and help choosing

HVAC USA is an authorized Lennox reseller, and everything we sell is new factory equipment. Your full Lennox warranty applies when a licensed, manufacturer-certified contractor installs your system and registers it within 60 days. Call or text (913) 364-0070, Monday to Friday, 9am to 5pm CST.