What Lennox Equipment is compatible with the S40 Smart Thermostat?
FAQ , Thermostats , Troubleshooting Modified: March 19, 2026
The S40 Smart Thermostat is designed to work with Lennox digitally-enabled furnaces (SLP99V, SLP98V, SL280V, EL296V and G71MPP), digitally -enabled ACs & heat pumps (SL28XCV, SL25XPV, XP21, XC21, XC20, XP20, EL18XCV, EL18XPV) and Lennox digitally-enabled air handlers (CBA 38MV).
While the S40 Smart Thermostat is designed for use with Lennox digitally-enabled equipment, the S40 Smart Thermostat can be used with the Equipment Interface Module (EIM) to work with almost any system. The EIM allows the S40 Smart Thermostat to work with Lennox-brand noncommunicating equipment and most other brands of heating and cooling equipment.
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