(S40) Smart T-Stat

Lennox International Inc

About this app

The Lennox Smart Thermostat App allows you to remotely access and control your Lennox S40 Smart Thermostat and advanced accessories from anywhere in the world. Whether it’s adjusting your home’s temperature or schedule, monitoring your indoor air quality or balancing room temperatures, the control is all at your fingertips.

You must own a Lennox Smart Thermostat (S40) to use this app. The Lennox Smart Thermostat must also be connected to your home’s Wi-Fi router before the app can control the settings. For more information go to https://www.lennoxsmartertogether.com/help/index.html

We truly appreciate your questions and comments. Please keep sending your suggestions to [e-mail] or @AskDaveLennox on Twitter

Ratings and reviews

This system is so buggy. I wish I could get my old system back with my Nest. The App is not reliable. Most of the time its not connecting so that you can not change a thing but it will show you that your changes were successful. The only way to make changes is to get in front of the S40. It forgets your assigned schedules if you switch it off. Temps are off all the time. I am wonder why so many customers have the same issue and Lennox does not do a thing and nobody goes to court.

We're trying to set up our new furnace and was told we needed to use this app for the initial setup. The app crashes every time I try to launch it, no error message, just flashes up a black screen and then goes away. Not feeling optimist about this new furnace..... Managed to get it working on a different phone and it seems fine, so not sure why it crashes on mine. Upped the review to 3/5 because it works half the time at least.

I have to use this app (as opposed to Nest, for example) because it is the only mobile app compatible with my Lennox heat pump system. But, it is a very unreliable and often buggy app! There is no active learning integrated, so schedules are not updated based on behavior. The Smart Away feature drains battery on my phone, and randomly is toggled off in the app (meaning I have to re-enable it if I want it to work again). I often see issues connecting to the thermostat, too.

What's new

At Lennox, we are continuously improving our products to better support your needs. For this release, we upgraded the security for Face and Fingerprint logins, improved Smart Away and fixed minor bugs. In addition, we removed support for 32-bit mobile devices.