Lennox S40 Smart Thermostat
Thermostats
The ultimate controller for more precise comfort
10-Year Limited Warranty
Features
We have higher standards. Others think so, too.
Year after year, leading institutions choose to award Lennox for its innovative initiatives in product design which helps homeowners define what perfect air means to them. Below you’ll find a recognition this product has received.
Take your home comfort system to the next level
Complement your home comfort system with our suite of technologically advanced accessories to more precisely and efficiently maintain the temperature and air quality in your home.
Smart Room Sensor Smart Air Quality Monitor Wireless Extender
Balanced Temperature and Humidity
The Feels Like™ feature creates the temperature you want to feel, not just the temperature you set—much like the "Feels Like" temperature in a weather report. So when you set it to 72 F, it feels like 72.
Schedule IQ Technology
Uses homeowner inputs and Smart Away™ geo-fencing capabilities to learn your routine and create a schedule that maintains comfort when the home is occupied and help save energy when it's not.
Efficiency at your fingertips
One-touch Away Mode overrides your regular programming schedule with a single touch and sets back your heating and cooling set points to save energy.
Digitally intelligent for precision and efficiency
Digitally intelligent for precision and efficiency
This truly digital product is part of a fully communicating home comfort system. Sensors in the equipment allow the thermostat to diagnose issues and automatically make system adjustments to more precisely and efficiently maintain temperature, humidity and air quality.
Complete control at home or away
Remote control of your home environment is just one touch or voice command away with the Lennox S40 Smart Thermostat. Monitor temperatures and schedules from anywhere in the world using the Lennox Home app on your smartphone or tablet. Available on the App Store and Google Play.
The Lennox S40 Smart Thermostat effortlessly integrates with a range of smart home devices—from premium smart home systems like Control4 to popular virtual assistants like Amazon Alexa and Google Assistant.
Advanced diagnostics keep your system at peak performance
Advanced diagnostics keep your system at peak performance
Protect your investment and peace of mind with active monitoring of system operations through your Lennox S40 Smart Thermostat. This feature is free of charge and provides basic maintenance reminders, alerts you of potential issues, and can even allow you to remotely share diagnostics with your local Lennox dealer to troubleshoot and fix problems. This proactive care helps eliminate downtime and avoid unnecessary service visits and repair costs, ensuring nothing short of perfect air.
The Ultimate Side of Perfect Air
Not only is the Lennox S40 Smart Thermostat part of the Dave Lennox Signature® Collection, it’s part of the Ultimate Comfort System™. This combines the best of everything Lennox has to offer to create an unprecedented whole-home comfort system that seamlessly and intelligently works together to stay finely tuned to your home and deliver consistently clean, perfect air.
Take your home comfort system to the next level
Complement your system with our suite of technologically advanced accessories to more precisely and efficiently maintain the temperature and air quality in your home. The Lennox Smart Air Quality Monitor is the only monitor of its kind that can detect air pollutants and trigger air cleaning on demand. Add on Lennox Smart Room Sensors to more evenly balance temperatures across rooms, plus the Lennox Wireless Extender to nearly double the connection coverage area and ensure you get the most from your communicating equipment. Altogether, it’s the most advanced accessories package available that delivers next-level perfect air.
Ratings & Reviews
See what other customers are saying about
Lennox S40 Smart Thermostat
5/5
Happy Buyer
March 02, 2025I purchased the S-40 a month ago with a new heat-pump system and back-up gas furnace for my home in Northern Utah. I find the S-40 to be user-friendly both when using the thermostat and the app on my iPhone and it has all of the features I need. That said, my needs are pretty simple, unlike some of the other reviewers. There was an initial issue with the thermostat displaying a temperature consistently 3 to 4 degrees higher than the actual temperature right in front of the unit. At first that issue stumped my HVAC company, but after some research they found there was a display temperature calibration adjustment in the advanced settings (plus or minus 5 degrees). Once that was adjusted it tracks the temperature accurately. I also appreciate the true variable capacity of my heat pump and furnace, so, while the S-40 is very expensive, getting the full functionality from the heat-pump and furnace was important to me and worth it. My home is a noticeably more comfortable with the temperature being more consistent without the wide swings of my old one-stage furnace. I also appreciate the 10 year warranty given how expensive the S-40 is to replace.
Yes, I recommend this product.
Sandy, Utah
Age: Over 65`
Gender: Male
Reason for Replacement: Planned
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