How do I add a new Lennox S40 Smart Thermostat to my existing account?
FAQ , Thermostats , Troubleshooting Modified: March 19, 2026
You can add a new Lennox S40 Smart Thermostat to your account by simply logging into the new thermostat with your existing account by going to Menu > User Account > Home info
Alternatively, you can add your new S40 thermostat to your account by using the mobile app, by entering a pin you generate on the thermostat.
To generate the pin, go to your thermostat, then go to Menu > User Account > Account and at the bottom of the page press the Generate Pin button. You'll be given a number that is unique for a one-time use.
When you enter the pin on your mobile app, you'll be automatically signed-in on your thermostat.
For more information or a visual representation of steps please reference our user guide here
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