Lennox S40 Smart Thermostat
Thermostats
The ultimate controller for more precise comfort
10-Year Limited Warranty
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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 Smart Thermostat 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
4/5
New S40 Thermostat Reads 2 Degrees High
September 06, 2024We replaced a Nest thermostat 11 days ago when our new thermostat, furnace and air conditioner were installed. The Nest also had an auxiliary thermostat that read the same temperature as the hallway Nest thermostat about 90% of the time but never more than 1 degree different between the two. I kept the Nest powered by the built in USB port so I could monitor the auxiliary thermostat temperature. Since the installation there is always a 2 degree difference between the Lennox and the Nest auxiliary thermostat. Yesterday I decided to move the auxiliary thermostat right next to the Lennox thermostat and now they both read the same temperature. I believe there is some heat coming off the Lennox thermostat due to the electronics and display being on constantly and due to the vent holes at the top of the case. Anyway, I moved the Nest auxiliary thermostat 4 inches from the Lennox case and the Nest auxiliary temperature dropped 2 degrees, similar to the difference in temperature when it was located in another room, as compared to the Lennox thermostat. Admittedly this isn’t a perfect test, but because there is a 2 degree difference when separated and no difference when right next to each other it would appear the Lennox thermostat sensor is affected by the small amount of heat that is being generated by its own electronics. Maybe it is the heat from the display. If this is what is causing the 2 degree difference, is there a fix for this minor problem?
Yes, I recommend this product.
Clinton Township, Michigan
Age: Over 65`
Gender: Male
Reason for Replacement: Planned
4/5
2/5
3/5
5/5
Works as advertised
July 03, 2024New system installed and the S40 hits all my needs. Easy programming and connection to WiFi. Is following my set schedule. What more could you ask for!? iPhone app is straightforward and easier than the Nest app it replaced.
Yes, I recommend this product.
NW Louisiana
Age: 55 - 65
Gender: Male
Reason for Replacement: Emergency
4/5
4/5
5/5
3/5
Works well, but screen is dim and no Apple HomeKit
June 13, 2024My S40 is part of a Lennox package of heat pump, hybrid furnace, and air cleaner I had installed 2 months ago. The devices do their work, but the thermostat could be quite a bit better on two fronts: screen quality and Apple HomeKit support. Screen quality: the display, even at its brightest, is difficult to read during the day. It is so dim that I disabled its auto dimming feature and proximity sensor and just leave it at maximum brightness at all times. Compared with other thermostats I’ve used, including Nest and Ecobee, this screen sucks! Apple HomeKit compatibility: I use HomeKit devices all around my home. The previous Lennox thermostat model, the S30, was HomeKit compatible, but for some reason this was eliminated with the s40. This is a major issue for me, as I have a number of smart home automations that either use data from the thermostat, or change thermostat settings based on other home conditions. I hope (faintly) that HomeKit compatibility will be added in the future.
Yes, I recommend this product.
Sunshine Coast, BC, Canada
Age: Over 65`
Gender: Male
Reason for Replacement: Planned
4/5
1/5
3/5
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