Lennox S40 Smart Thermostat
Thermostats
The ultimate controller for more precise comfort
10-Year Limited Warranty
Features
Ratings & Reviews
See what other customers are saying about
Lennox S40 Smart Thermostat
4/5
Lighted view
November 23, 2025The only problem is the screen. The white of the numbers are too small to see properly across the room. It’s predecessor was easily viewed no matter what the light in the room is
4/5
4/5
Great Display and Easy to Use
November 15, 2025Just got this thermostat installed 2 weeks ago. I really like the display and ease of use, especially the perfect temp feature that allows me to set one temperature and it will heat and cool without separate set points. The app works great. The only issue/bug I’ve noticed happens if you have a scheduled program running and then if you change the unit settings on the app, the system will stop operating. To fix I had to change the unit back to what it was when the schedule was setup and then restart the system.
Yes, I recommend this product.
5/5
4/5
3/5
3/5
Great thermostat, but missing key feature
October 07, 2025I’ve had a Lennox system for a while using the S30 thermostat, and loved that it worked with Apple HomeKit. However, the S30 lost communication with devices constantly. It was replaced with the S40, which is much more reliable. Haven’t had a single issue. Sadly though, I miss the HomeKit compatibility. I’m really hoping that Lennox can add it back in an update at some point.
Yes, I recommend this product.
Bossier City, LA
Age: 45 to 54
Gender: Male
Reason for Replacement: Emergency
3/5
4/5
5/5
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