Sensi Lite Smart Thermostat, Data Privacy, Programmable, Wi-Fi, Easy DIY, Works With Alexa, Energy Star Certified, ST25, Most Systems C-Wire Not Required, Except On Heat/Cool Only and Heat Pump System
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Sensi Lite Smart Thermostat, Data Privacy, Programmable, Wi-Fi, Easy DIY, Works With Alexa, Energy Star Certified, ST25, Most Systems C-Wire Not Required, Except On Heat/Cool Only and Heat Pump System

4.1/5
Product ID: 522936134
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Details

  • Brand
    Emerson
  • Model Name
    Sensi Lite
  • Product Dimensions
    0.88"D x x
  • Controller Type
    Hand Control
  • Special Feature
    Filter Low
Save 23% HVAC energy
📶Wi-Fi remote control
🔒Data privacy guaranteed

Description

🌡️ Stay smart, save energy, and keep your privacy intact!

  • EFFORTLESS DIY SETUP - Built-in level & step-by-step guide for quick, no-fuss installation.
  • PRIVACY FIRST DESIGN - Your data stays yours—no selling or ad targeting, ever.
  • SMART ENERGY SAVINGS - Energy Star certified with flexible scheduling and geofencing to cut costs by 23%.
  • UNIVERSAL COMPATIBILITY - Fits most HVAC systems without a C-wire, simplifying upgrades for modern homes.
  • SEAMLESS VOICE APP CONTROL - Works with Alexa, Google Assistant, and SmartThings for hands-free comfort.

The Emerson Sensi Lite Smart Thermostat (ST25) offers easy DIY installation with built-in leveling and clear instructions. Compatible with most HVAC systems without requiring a common wire except for heat pump or heat/cool only setups. It’s Energy Star certified, helping users save about 23% on HVAC energy costs through programmable schedules, geofencing, and remote app control. Privacy is prioritized with no data selling or ad targeting. Control is seamless via Wi-Fi, Alexa, Google Assistant, and SmartThings, making it a sleek, efficient upgrade for modern smart homes.

Large manufacture image 1Large manufacture image 2

Specifications

BrandEmerson
Model NameSensi Lite
Product Dimensions0.88"D x 5.07"W x 3.13"H
Controller TypeHand Control, Google Assistant, Amazon Alexa, SmartThings
Special FeatureFilter Indicator, Low Voltage, Auto Changeover, Daylight Savings Time Ready, Programmable
ColorBlack
Specific Uses For ProductBoiler, Heat Pump, Air Conditioner, Furnace
Temperature Control TypeAutomatic or Programmable
Connectivity TechnologyWi-Fi
Included ComponentsInstallation Guide, Sensi Lite Smart Thermostat, Mounting Hardware, Wire Labels, (2) AAA Batteries
Power SourceBattery or C-wire
Item Weight4.8 ounces
Voltage24 Volts
ShapeRectangular
Display TypeLCD
Control MethodApp
Connectivity ProtocolWi-Fi
Mounting TypeWall Mount
StyleSimple
BacklightYes
Specification MetEnergy Star
Number of Batteries2 AAA batteries required. (included)
UPC786710568732
ManufacturerEmerson
Control TypeApp Control
Part NumberST25
Country of OriginMexico
Item model numberST25
Batteries2 AAA batteries required. (included)
Size0.88 x 5.07 x 3.13
PatternThermostat
Item Package Quantity1
Special FeaturesFilter Indicator, Low Voltage, Auto Changeover, Daylight Savings Time Ready, Programmable
Batteries Included?Yes
Batteries Required?Yes
Battery Cell TypeAlkaline
Warranty Description3 years.

Have a Question? See What Others Asked

How does the auto changeover work? can i set it to keep the temp between 65 and 74 degrees and it turns a/c and heat on as necessary?
Hi. My old thermostat has the red wire connect to RH which then jumps to RC. With the Sensi lite, do I just attached the red wire to R? Thank you.
Will this thermostat work on a split unit meaning natural gas heat
Does this have a child lock?

Reviews

4.1

All from verified purchases

J**.

Easy to use and works great!

This was purchased for a church building where areas are unoccupied at various times. This first purchase was a trial. The heating system is hot water with a central boiler serving several zones.We found this thermostat much easier to install and program than a previous brand we had we had tried to use. It connected easily with our existing Wi-Fi. For our system (heat only) it required a “C” wire but fortunately the existing wiring contained a wire we could repurpose. We haven’t used the early start feature yet we’ve just estimated the time to achieve the set temperature and programmed the system to come on soon enough to achieve it. A conversation we had with the the help line informed us that the thermostat will learn the time needed to achieve the correct temperature.The one call to the help line was very useful. The wait to be connected was fairly long, 15 minutes or so, but the gentleman was very knowledgeable and able to answer all the questions we asked. We have also emailed a question and received an answer but the response is slow.We’re pleased with the appearance of the unit it looks very solid and it’s not obtrusive and it is also easy to read. We also like the fact it can be locked to prevent unauthorized adjustment.It has been convenient and easy to install the app on multiple phones and nice to be able to check and adjust programs remotely. It is also nice that it connects to some weather information and displays the outside temperature.It’s great to have the room at a comfortable temperature when you expect it to be.We will also connect the a/c system to it later which now runs on a separate device.We have been pleased with the unit and have ordered two more for other areas.

A**R

Simplicity and connectivity is keen

After Amazon Thermostat, this is totally different experience. Was surprised with quality and connectivity and simplicity of installation. I bouth 2, the full version and lite version, so far so goodWas using for about 3 weeks. Got notifications when door is open, I can set up limit on temperature, which is Incredibly useful for rental.

R**E

Smart thermostat

Works very well, easy control on my phone

B**D

Poor connectivity

I have a home that was built in 2006 and I work in a technical field (engineer) so I am familiar with troubleshooting hardware/software problems. Anyway, my problems with this unit started immediately. During installation, one is supposed to note the letter codes that the existing thermostat is connected to so that the new thermostat can be notified (via wifi and on app on your phone) how to program its terminals to match the original thermostat's functionality. Unfortunately, my existing wire connection was not recognized as being valid by the app (even though my home is relatively new, has a C wire and works properly with the original controller). I didn't let the this deter to me as I was sure I could fine a setup that would work through a little trial/error and voltage measurement. I was able to program my thermostat the first time without any issues; however, the setup I entered didn't work (system produced heat when it should have been cold), so I tried to reprogram the thermostat for a 2nd try. When I searched for my wifi network on the app, I was informed that no networks could be found, which was strange since all my other devices (computers, tablets, TVs, etc) had no issues connecting to my wifi. No problem I thought because I was given the option of entering the name of a network manually, which I did. After entering the name I was asked to enter the network's password twice, which is also strange since double entry is typically required for setting up online accounts, but not for connecting to your own wifi. Anyway, I entered the password twice and things seemed to be okay for a short time, but then the app kept informing me that it was losing its connection to the thermostat. I put the thermostat in "setup" mode by pressing the mode button for 4 seconds, but the thermostat would only stay in setup mode for a few seconds, and whenever it popped out of setup mode, the app would lose its connection again. What was really frustrating is that every time I tried to change the setup, I had to enter the network name and the password twice, which is pretty dumb for a "smart" device! I fought the system for about 2 hours and I was finally able to get another setup programmed, but that one didn't work either. At this point I decided I was done fighting the thing and I returned it. Again, I'm a competent technical person and my heat pump is relatively new and in good working condition. If I can't get it working smoothly, I don't think many others will be able to either. Perhaps I just had a lemon, but my advice is to steer clear of this finicky little monster.

A**E

'Smart' heating thermostat

I chose this product because reviews indicated that it would work with a 2-wire heating system, despite the instructions that it required a C-wire. The bad news is that the thermostat will control the heater via the "R" and "W" wire posts using a manual temperature setting, but it will not work with the Sensi app, which is the whole point, right?But there is a solution! I bought "UL Certified Thermostat C Wire 24V Transformer, White Adapter Compatible with Honeywell, Nest, Emerson, Ecobee, Wyze Thermostat and Most Doorbells" and lo and behold it works! Just connect one wire from the transformer (24VAC) to the same post as the "R" wire and the other transformer wire to the "C" post. It does not matter which transformer wire that you connect to the "R" and "C" posts - AC remember?Set up with the Sensi app proceeded pretty well with a bit of try-agains. It seemed that after scanning the supplied QR code with the Sensi app and starting the configuration, the thermostat dropped the wifi connection. The second try worked like a charm, however. Its not due to the wifi signal either - I bought two of these thermostats, one upstairs and one downstairs - same exact result.Now for the Sensi app itself. Setting up a schedule was easy and works well. The geofencing isn't as customizable as I would like, because it only adjusts the temperature setting by 4 degrees. I would like a bigger adjustment when I am away, but this is not possible. I would also like to see more usage statistics in the app. The usage display is rather simple and not very informative. I would also like to control the temperature display on the thermostat, such that it turns off at night, but I don't see how this can be accomplished in settings. Oh well, there is always electrical tape!.

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TrustScore 4.5 | 7,300+ reviews

Ayesha M.

The product exactly matches the description. Very satisfied with my purchase.

5 days ago

Fatima A.

Best international shipping I've ever tried. Worth every penny!

3 days ago

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