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Lennox

S40 WIFI 3HT/2CL Smart Stat

  • Based on 217 reviews
Condition: New
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Availability: 18 left in stock
Fulfilled by Consumer Supply Co
Arrives Jul 23 – Jul 25
Order within 16 hours and 23 minutes
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Features

  • To provide worry-free 10 year warranty against manufacturing defects or defects. To maintain warranty validity, it is necessary to hire a certified HVAC loader for proper installation. Failure to use a professional HVAC loader may render the warranty void. If the thermostat is not professionally installed, the item cannot be returned or returned. How to register for warranty, instruction included in the box.
  • It has a 7 inch high resolution color screen for easy readability. User-friendly touchscreen for easy system configuration and maintenance alerts. Using geographical fencing technology, multiple programs offer One-Touch Away Mode and Smart Away feature.
  • Compatible with 4-wire standard thermostat cables, use protected thermostat cable to prevent noise interference. Works with most 24VAC ovens, air conditioners, air conditioning processors and heat pump (up to 3-stage heat and 2 cooling stages) outside of the communication of HVAC equipment outside LENNOX.
  • Compatible with traditional HVAC systems with optional Equipment Interface Module (EIM) for control. The Smart Zoom System (iHarmony) allows the entire home improvement with full control from the S40 Smart Thermostat.
  • On-Demand Weather provides live weather data and seven day forecasts. Quickly set up and configure with the Lennox Smart app. Installer setup displays allow quick system configuration without manuals.
  • Test on the entire system or individual components for maintenance and troubleshooting. Service Panel allows real-time monitoring of installed smart systems.
  • Improve temperature and air quality control with advanced accessories such as Smart Room Sensor, Smart Air Quality Monitor and Wireless Expander. Taking insights from digital controls and through the PureAi S Air Purification System to maintain efficient working conditions.

Description

Product Overview Lennox S40 Smart Thermostat, Touchscreen, Communicating, WiFi, Programmable, 3 Heat/2 Cool The S40 Smart Thermostat recognizes and connects to all Lennox communicating products to automatically configure and control the heating/cooling system (based on user-specified settings) for the highest level of comfort, performance and efficiency. S40 Smart Thermostat also recognizes model and serial number information for Lennox digitally communicating products to simplify system setup. Learn more about the S40 Smart Thermostat below or visit the S40 resource hub for all your dealer needs. 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 and Wireless Extender Advanced digital controls in specific heating and cooling units and the PureAir S Air Purification System communicate information about various operating parameters to the thermostat to constantly maintain the most efficient operating conditions possible Additional conventional (non-communicating) indoor air quality comfort products (Healthy Climate Humidifiers, Humiditrol Enhanced Dehumidification Accessory, Healthy Climate HRV/ERV Heat/Energy Recovery Ventilators, Fresh Air Damper, Healthy Climate Germicidal Lights) can be added to the system for a complete total- comfort system Conventional HVAC systems (non-communicating) can be controlled by the S40 Smart Thermostat with the addition of the optional Equipment Interface Module (EIM) Optional Smart Zoning System (iHarmony, for specific HVAC systems) allows whole-home zoning (up to 4 zones) with complete control from the S40 Smart Thermostat and individual In-Zone Thermostats A simple easy-to-use touchscreen allows complete system configuration. Scheduled maintenance alerts, system warnings and troubleshooting are also displayed on thermostat screen Up to four separate schedules are available plus Schedule IQ One-Touch Away Mode - a quick and easy way to set the cooling and heating setpoints while away Smart Away - Schedule IQ uses geo-fencing technology to determine when the homeowner is within a predetermined distance from the home to operate the system when leaving, away and arriving Weather-On-Demand - live up-to-date weather data and seven-day forecasts Easy to read 7 in. high- definition color display (measured diagonally) New Lennox Smart Technician app allows for quick and easy install of S40 Smart Thermostat and the new smart accessories Installer setup screens allow quick and simple system configuration without a manual Installer can also run tests on complete system or individual components for easy maintenance and troubleshooting Service Dashboard features online real-time monitoring of installed smart digitally enabled systems Uses 4-wire standard thermostat wiring. We highly recommend using 18 - 22AWG shielded thermostat cable for communications terminals (I+ and I-) which will help eliminate any noise interference. Note: The Lennox S40 Smart Thermostat with Equipment Interface Module (22X18) will work with most 24VAC furnaces, air conditioners, air handlers and heat pumps (up to 3 stages of heat and 2 stages of cooling), EXCEPT IT WILL NOT WORK with any brand of communicating HVAC equipment other than LENNOX.

Brand: Lennox


Model Name: S40


Special Feature: Programmable


Color: Black


Additional Features: Programmable


Specific Uses For Product: Air Conditioner, Heat Pump


Temperature Control Type: Automatic


Connectivity Technology: Wi-Fi


Power Source: Corded Electric


Voltage: 22 Volts


Display Type: touchscreen


Screen Size: 7 Inches


Control Type: Touch


Control Method: App, Voice


Connectivity Protocol: Wi-Fi


Mounting Type: Wall Mount


Backlight: Yes


Smart Home Compatibility: Smart Home Compatible


Brand Name: Lennox


Model Name: S40


Included Components: Smart Room Sensor, Smart Air Quality Monitor, Wireless Extender, Lennox Smart Technician app, Equipment Interface Module (EIM), In-Zone Thermostats


Model Number: 22V24


Manufacturer Part Number: 22V24


Unit Count: 1.0 Count


Color: Black


Shape: Rectangular


Product Style: Modern


Material Type: Glass, Plastic


Finish Types: Glossy


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Jul 23 – Jul 25

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Similar Products

Top Amazon Reviews

    • Lennox has flagged as being from a stolen shipment Lennox has flagged as being from a stolen shipment
Review Image by EJ Honda
Review Image by EJ Honda
UPDATE 5/14/26: came home today to my new Lennox S40 thermostat displaying a message saying it was from a stolen shipment and functionality is limited! See pic. Reseller and Amazon quickly issued a full refund for the thermostat. Original: After 12 years, my previous Lennox iComfort 10f81 WiFi thermostat started having screen issues, so I started digging into my options. So glad I found information indicating this S40 thermostat was a viable replacement (the older 10f81 thermostat is no longer manufactured and can only be purchased used, for about the same price or more than this new S40). This S40 is a huge step up in functionality, and the excellent Lennox Home app is lightyears ahead of the dated Lennox iComfort WiFi app. So much so, I'd consider recommending folks upgrade their thermostats even if their 10f81 is still functioning. Install was a breeze since the wiring is the same between the wall plate connectors. Just note what color wire goes to each of the R, I+, I-, and C terminals. They're in the same order on the S40 wall plate, but I did note my 10f81 used Philips set screws while the S40 set screws were flat head. The 10f81 set screws required the wiring to connect to the bottom of the terminals, but the S40 terminals had the wire ends coming into the top of the terminals. The wall plate for the S40, while slightly smaller than the 10f81 plate, has wider spaced mounting holes, requiring new holes in the wall, but the old ones will be covered by the plate. I made sure to turn power off to the furnace as suggested in installation documentation prior to rewiring to the new wall plate. I also used blue painters tape to keep the new S40 wallplate in place while I decided where the new mounting screws needed to go, starting with drilling one screw into the wall, then using a level to determine where the next screw needed to be placed in order to keep the plate level. I used a short level, balanced on the top two mounting prongs the thermostat will eventually click onto. Was pleased to feel how much less effort is needed to snap the S40 thermostat on and off compared to the old 10f81. Turned the furnace back on and waited for the thermostat to power up and initialize itself. The longest part of this install was the software set up of the S40. It's easier if you install the Lennox Home app on your phone FIRST, create a Lennox account if you don't already have one, and get logged into the app before proceeding. I added my HVAC company's phone number when prompted, but that was about it, skipping the rest of the dealer setup portion. Supposedly you lose the 10 year warranty without dealer installation, but reading about the crazy expensive installation costs, I figured it'd be cheaper to just buy another thermostat if needed. My guess is that you're actually buying that 10 year warranty through the dealer's install fee, but that's just a theory. ... show more
Reviewed in the United States on April 18, 2026 Reviewed in the United States on April 18, 2026 by EJ Honda
    • Lennox S40 Thermostats Identified as Affected Shipment Inventory Lennox S40 Thermostats Identified as Affected Shipment Inventory
Review Image by Shopper
I purchased two units of this product during a promotion from a seller named AR TECH USA. The thermostat itself works very well, and I was initially very happy with the price, product quality, and functionality after installation. However, after setup, both units displayed a permanent warning message stating they were identified by Lennox as part of an affected shipment. Lennox confirmed the serial numbers were flagged and informed me that warranty coverage and manufacturer support would not be provided for these units. The seller eventually issued a refund but could not provide legitimate replacement inventory. The warning message also cannot be removed even after a factory reset. Since my older thermostats had already been discarded after the new units were installed, this has left me without an easy replacement solution at this time. I also contacted Amazon customer service, but beyond the refund, no additional replacement assistance was provided. Buyers should understand that if they receive affected inventory, replacement and support options may be very limited, even if the thermostat itself functions properly. I would strongly recommend verifying that the products are sourced through authorized channels before purchasing. ... show more
Reviewed in the United States on May 16, 2026 Reviewed in the United States on May 16, 2026 by Shopper
    • A solid DIY upgrade from the Lennox 10F81—especially if you catch it on sale A solid DIY upgrade from the Lennox 10F81—especially if you catch it on sale
Review Image by Retired Navy Veteran
Review Image by Retired Navy Veteran
Review Image by Retired Navy Veteran
Review Image by Retired Navy Veteran
Review Image by Retired Navy Veteran
Review Image by Retired Navy Veteran
A quick note on installation: While this can be a DIY project, if your Lennox system is still under warranty, you should probably let a licensed tech handle it to avoid any issues with coverage. I didn’t upgrade by choice—my Lennox 10F81 display suddenly went blank one day. It still had power, but the screen was completely unresponsive, so I had no way to control the HVAC. Since that model isn’t even available on Amazon anymore, I went with the Lennox S40. After installing and dialing it in, it honestly feels like I have a whole new system. Installation was easier than I expected. The mounting is very similar to the old unit, and I used the same 4 wires (confirmed 24VAC on the R wire using the C wire as the common—see my wiring photo). I didn’t have to patch or repaint anything since two of the original screw holes lined up perfectly. The screen is clear and responsive, though it can be a little slow when entering things manually. The weather screensaver is a nice touch when it’s idle. The app walks you through setup step-by-step—just take a picture of your old wiring first so you don’t have to guess. I also added it to Alexa, which was simple. I used ChatGPT a bit to help fine-tune the “feels like” temperature and humidity settings. I’m retired and home most of the day, so I built a schedule that actually fits how I live. I didn’t want to rely on geofencing “guessing” when I’m home or not; for me, the cost to reheat the home after being away a few hours is minimal anyway. Right after installing, it flagged an airflow issue. Turned out to be a dirty humidifier pad—something I never would’ve caught with the old thermostat. The diagnostics alone make this worth it. I’ve since set 6-month reminders for my filter and pad so I don’t forget down the road. I also have Allergen Defender turned on using my zip code. It monitors local air quality and runs the system more when pollen is high, which is a nice bonus. Comfort-wise, humidity control is the biggest difference. With dew point and the humidifier working together, the house feels warmer without turning the heat up (running at 71° "Feels Like" at 36% humidity feels perfect). Once I got everything set (72–75, cooler at night), I stopped touching it. No big swings, no constant adjusting. Price-wise, I paid $387.98 total. The unit was on sale for $329.98 (about 62% off), plus $45 overnight shipping and no tax. At that price, it made sense. If you’re coming from a Lennox 10F81—or dealing with a blank screen—this is the upgrade path. Compared to the 10F81, the S40 actually feels like it’s managing the system instead of just reacting to it. ... show more
Reviewed in the United States on April 9, 2026 Reviewed in the United States on April 9, 2026 by Retired Navy Veteran
    • Review of swapping in the latest S40 for defective Legacy Icomfort Wifi "communicating" thermostats
I was replacing a previous Icomfort Wifi "communicating" thermostat (circa 2016) which had glitchy wifi and eventually the screen died. I Iost both local and remote control capability. The S40 turned out to be the latest compatible model that would drop into the existing t-stat wiring without having to touch any wiring over at the furnace. non-lennox smart thermostats (such as Nest, honeywell, etc), will not work as a replacement without also re-wiring over on the furnace. I wanted to avoid touching the wiring on the furnace. a quote thru an authorized lennox installer was north of $1700 (parts and labor) for me. purchasing the thermostat off Amazon was considerably cheaper and the installation was straightforward. there are some videos online which are good references. The setup I have is a lennox Elite EL296 (gas) furnace with a single stage Lennox Elite A/C and lennox healthy climate bypass humidifier. Of these three pieces, only the EL296 furnace is smart (2-stage heating, variable speed fan). the A/C is single stage and is an "on" or "off" control....the bypass humidifer was also "on" or "off". according to the S40 box, it has labelling that states it is compatible with the Signature, Elite, and Merit series furnaces. you don't have to touch the wiring on the furnace side, but if you were to open the furnace front cover and remove 2 screws to open the service door, you would see the thermostat wiring connected to terminals R, I+, I-, C. the A/C and the bypass humidifier are simple 2-wire connections into other ports on the furnace ...no communication happens with the A/C or humidifier in my setup.....the thermostat will communicate to the furnace to turn these items on or off. installation notes: -very important to turn off all power to the furnace before re-wiring the new thermostat. you don't want any surges to damage your new and expensive thermostat. Use the emergency electrical shutoff switch....if that is not accessible, turn off the power at the circuit breaker -the system uses 4 wires. in my case, I have 5 wires and the previous installer had tied 2 wires together into the "C" port. the same 2 wires were connected to the "C" port at the furnace side. note the color of each wire and where it goes....(R, I+, I-, C).....you'll connect to the same terminals on the new thermostat. -after re-wiring, mounting the backplate to the wall, and securing the thermostat to the backplate....turn on the power. thermostat should boot up with a Lennox logo. -follow the directions on the front panel. you can choose to setup using a "lennox technician app" or use the touchscreen on the S40. I opted for the front panel. -after accepting all terms and conditions/privacy/etc.....follow the prompts. when asked to enter dealer ID or phone numer, just skip that screen. Thermostat will auto-detect equipment. in my case, it detected the main furnace model/serial #, plus a single stage A/C and humidifier. NOTE: on this screen, press the A/C setting which will bring up a window which can allow you to adjust the A/C capacity. in my case, I googled the model # of my A/C and it stated it was 2.5ton...another bit of googling converted the tonnage to 30kBTU...so I set the capacity at 30kBTU. this is probably the most sophisticated setting to deal with (IMO) -you will finally get to a screen to run thru tests. go ahead and select all and conduct the tests to check that the fan runs, the heat runs (stage 1 and stage 2 in my case), A/C runs, and humidifier runs. -after testing, you can exit that menu. system should be idle (off).....then go into settings on the S40 to turn on your preferred schedule (summer, winter, spring/fall, custom, Smart). you can then edit the temperatures and timings to your preferences. -lastly, it pays to install the lennox home app and then pair the app and thermostat so that you can have full remote control. it will also allow control via Alexa....and you can enable options such as Geofencing, so the system will setback temperatures based on your GPS data...by default geofencing is turned off. -I took my time, so installation (mounting to wall, re-wiring, and software setup) was probably 30-40min -the S40 uses the new Lennox Home app.....this is different than the legacy Icomfort Wifi App for the older thermostat. ... show more
Reviewed in the United States on September 1, 2025 by VSA
    • Stolen Unit Stolen Unit
Review Image by Maria Green
Like the other reviewers, my item was apparently part of a stolen lot. The thermostat otherwise works well. The QR code cannot be removed; we will need to install a new unit.
Reviewed in the United States on June 16, 2026 Reviewed in the United States on June 16, 2026 by Maria Green
    • if you have to replace your Lennox thermostat, this one works
If you are like so many others who invested in a new Lennox HVAC with an iComfort thermostat that stopped responding once the warranty is out, you will need to upgrade to the current version of thermostat. I had purchased a Nest only to find out that Lennox has a proprietary system that only works (well) with their own very expensive proprietary thermostat. I had a service person come out to replace the dead unit only to be told it would be over $2K for him to replace it. However, he was able to tell me which thermostat I needed to buy and gave me basic instructions if I chose to install it myself. Shopping on Amazon, there are several vendors selling this thermostat and I chose this one with a price at almost half of all the rest. I watched a couple of videos on how to install and chose to save money and do it myself. I took pictures of the wiring and followed the instructions. The only hiccups I had were getting the thermostat to connect to the mobile app and wondering what to enter for a dealer code/phone number. There are a lot of features on this thermostat. You can set auto high and low temps depending on the time of day. The mobile app will keep trying to reset the high temp to 78 or 84 and going back and forth to the screen, I was finally able to convince it that I really did want my daytime temp to be 72 and night time temp to be 68. This house is never empty and there is no thermostat on the second floor. It gets very warm working up there. You can set the device to show the actual temp inside and outside as well as the "feels like" temp. You can set the default screen to a photo if you like. Overall, it appears to be working after less than an hour of set up. I would drop stars for the price since this is way over priced compared to other thermostats and I really dislike that Lennox produced such a poor quality thermostat that had to be replaced with their newer version at an exorbitant price. ... show more
Reviewed in the United States on April 3, 2025 by M. Schaefer
    • Yes, this is the replacement to the older screens and it's easy to install.
Yep, I had the older Lennox touchscreen unit...sorry, I forget the old model number...that experienced the dreaded dead screen. Like many other users, I was dismayed to see the replacement model recommended for professional install, raising the cost beyond kind words. Well, install is pretty easy. With the right instructions, it took me five minutes with a small screwdriver. No biggie. This thermostat works to control my lennox HVAC. The screen has some nasty lag, so it's actually easier to use the app on the phone sometimes. There are some flashy features, like the ability to use your own photos for the background and smooth app integration. I can even set it to give me a monthly summary of system usage, which is not important, but it's kinda fun. It has easy to check weather forecasts built in (as though we walk to the thermostat to check the forecast). It's also got highly programmable settings for single/multi zone and times of day that's all easy to customize. Most importantly, if you're looking for the current replacement to the touchscreen Lennox thermostats from 5-10 years ago, this was the right unit for me. Installing it was easy for me, no technician required, since it uses the same wires as my old thermostat required. Other brand smart-thermostats seem to require other wiring. So, even though the unit is pricey, it was the right way to fix my system myself, and avoid costlier technicians doing what I can with a single screwdriver. In summary, it works, it's easy to install for Lennox HVAC systems, and it has a few features. If you're checking out this model because it's the current replacement for your older Lennox thermostat, yes choose this and install it yourself. ... show more
Reviewed in the United States on August 20, 2024 by M. Acker
    • Works well but has an error QR code that says it was stolen! Works well but has an error QR code that says it was stolen!
Review Image by CShiff
Purchased this as a “new” item from Amazon, had it installed a month and it worked well but now has a QR code on the screen stating that it was from a stolen shipment lot through Lennox company.
Reviewed in the United States on May 14, 2026 Reviewed in the United States on May 14, 2026 by CShiff

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