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Emerson Thermostats

Emerson Sensi Wi-Fi Smart Thermostat for Smart Home, DIY, Works With Alexa, Energy Star Certified, ST55

    • Based on 20,221 reviews
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Availability: Only 1 left in stock, order soon!
Fulfilled by Amazon
Arrives Sunday, May 12
Order within 5 hours and 24 minutes
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Style: DIY


Pattern Name: Thermostat


Features

  • PRIVACY PROTECTION*: Sensi wont sell your personal information to third parties
  • SAVE ABOUT 23% ON HVAC ENERGY*: The ENERGY STAR-certified Sensi smart thermostat can help you save energy with features like flexible scheduling, remote access, and usage reports
  • EASY DIY INSTALLATION: Use the built-in level and step-by-step app instructions for a quick installation. Works with HVAC equipment found in most homes. Common wire (c-wire) is not required in most applications
  • SMART MAINTENANCE: Sensi can help monitor the performance and efficiency of your HVAC system by delivering valuable usage reports, alerts about your equipment, and maintenance reminders like filter replacement
  • SIMPLE CONFIGURATION: Looks and feels like a thermostat. Has buttons and fits the same space as a traditional thermostat so you dont have to patch and paint your walls

Description

Sensi smart thermostats are designed for energy savings and data privacy – to give you full control of your home HVAC. With over 100 years of HVAC experience and manufactured by Emerson, you know our expertise already, even if you didn’t realize it. Emerson produces many of the HVAC parts that our smart thermostats control, so you can feel confident in the product you put on your wall. With our top-rated mobile app and easy installation process, customers of all comfort levels can make the switch to a Sensi smart thermostat. In addition, our customer service team of HVAC experts is always available to help you through any questions you might have. For more information on Compatibility, Energy Savings, and Privacy Protection, please refer to the “Product Documentation” section below.

Brand: Emerson Thermostats


Model Name: Wi-Fi Thermostat for Smart Home, DIY Version


Product Dimensions: 1"D x 5.88"W x 3.75"H


Special Feature: Filter Indicator, Clock Display, Fan Control, Auto Changeover, Daylight Savings Time Ready


Brand: Emerson Thermostats


Model Name: Wi-Fi Thermostat for Smart Home, DIY Version


Product Dimensions: 1"D x 5.88"W x 3.75"H


Special Feature: Filter Indicator, Clock Display, Fan Control, Auto Changeover, Daylight Savings Time Ready


Color: White


Specific Uses For Product: Boiler, Heat Pump, Air Conditioner, Furnace


Connectivity Technology: Wi-Fi


Included Components: Thermostat, free mobile app, 2 AA batteries, mounting hardware, wire stickers, installation guide, welcome guide with Sensi code, warranty booklet


Power Source: Corded Electric


Item Weight: 13.6 ounces


Voltage: 24 Volts (AC)


Material: Plastic


Shape: Rectangular


Display Type: LED


Screen Size: 5 Inches


Control Type: Button Control


Control Method: Voice


Connectivity Protocol: Wi-Fi


Mounting Type: Wall Mount


Style: DIY


Backlight: Yes


Number of Batteries: 1 AAA batteries required. (included)


Department: Unisex-Adult


Manufacturer: Emerson Climate Technologies


Item model number: ST55


Batteries: 1 AAA batteries required. (included)


Is Discontinued By Manufacturer: No


Assembly required: No


Number of pieces: 1


Warranty Description: 3 years.


Batteries required: Yes


Import: Made in the USA


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Sunday, May 12

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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Top Amazon Reviews

    • Easy set up and works flawlessly!
Style: DIY Pattern Name: Thermostat
I was looking for a smart thermostat without breaking the bank and without the need for any fancy features like self learning based on your habits for example. Got a good deal on the Sensi and decided to try it out. I downloaded the app before purchasing and was able to check my existing wiring to see if the Sensi was compatible for my system. The app is simple and goes through the all the necessary steps for set up. You will need the C wire for this thermostat. Once I confirmed compatibility, and after delivery, following the instructions on the app took me through the process of removing the old thermostat and installing the Sensi. It was a very easy and logical process which even a novice at home improvement can follow. The only slight hitch in setting up the system was ensuring that the wire connection was secure - a couple of the wires came loose after I thought I had screwed them in. Really not a big deal but I gently tugged on the wires to ensure that they were not loose. The Sensi thermostat attaches to The wall by clipping into the wall plate that is provided. Luckily for me the old wall plate holes were in the right spot for the new Sensi wall plate. Before clipping the thermostat on ensure that the wires are flush with the wall as instructed by the app. Connecting to WiFi was fairly easy and it was done through the app on my iPhone. The thermostat is only compatible with 2G WiFi so you have to make sure your phone is connected to the 2G network while going through this part of the setup if you have a dual band router (you can switch your phone back to the 5G network after if you wish). WiFi connection was made quickly although the thermostat did take 30 or so seconds to be fully responsive to my phone after I thought the connection was completed (I initially thought I needed to go through a troubleshooting process but did not need to complete that process). Once fully connected you can easily adjust temperatures in the app, set up schedules and use a variety of options e.g. display humidity etc. There is also a geofencing option if you wish to use that. I set up my iPhone to be able to use Siri to adjust temperatures. You’ll need to set up your iPhone Home app for that. Once again the app runs you through all the steps to do that. I also set up my wife’s phone for her to have the feature that allows her to use Siri. Initial attempts to set her Home app to connect with the thermostat using Siri were unsuccessful until I realized that I could simply share my iPhone Home app settings with hers (just had to make sure to switch to the shared home app profile and not the original default one on her phone). If you do not wish to use Siri you can simply use the controls in the Sensi app and do not have to go though the Home app set up. I’ve had the thermostat for a week now and I love it. The thermostat is very responsive to changes made within the Sensi app or when using Siri (usually within 1-2 seconds). I also like that I can view ‘Usage’ within the app to see how long the furnace has been active. The app will also allow you to check to see if you are eligible for rebates based on energy savings programs for your area. Of course if you need to change app settings on the thermostat itself it is very easy to do so. There is a feature in the app that allows you to lock the wall display and only be able to change settings, temps etc through the app if you do not want people to change temps or settings through the wall display. Overall a great thermostat. Easy setup. Easy to use. Great features. Very responsive when using your phone. 5 stars plus!! ... show more
Reviewed in the United States on December 7, 2019 by Mel
    • Great!
Style: DIY Pattern Name: Thermostat
I really like this thermostat. I had one for about a year, and I just installed another one on the other side of our house. It’s very simple, but also does the Wi-Fi thing very well. Scheduling, humidity monitoring, statistics, it all works very well. The app is excellent, it’s very simple and works great. Installing it also was very easy, even without a c-wire. i’ve seen other reviews say that the batteries don’t last very long. This is not in the case in anyway for me. As I said before, I’ve had one of these for about a year – with the same set of batteries. And if you look at the battery meter it still has full three stripes, that is the battery is still totally full after a year. So at least in my experience, you don’t have to worry at all about not having a C wire – the battery seems to be working 100% OK. so, I would totally recommend buying this. Again, I bought a second one because I liked the first one so much. It’s not very expensive, it’s simple and it works great. ... show more
Reviewed in the United States on March 18, 2024 by Phillip C. Adkins
    • Great basic smart thermostat unit and does not require c-wire
Style: DIY Pattern Name: Thermostat
Wanted to upgrade the thermostat unit but my wiring didn't include the c-wire which removes many other options from the table. Luckily the ST55 doesn't require it (and instead uses batteries). The ST55 is actually Emerson's lower tier smart thermostat, and doesn't have a lot of the bells and whistles of their higher end units. The design is also much more traditional, as opposed to the higher end units, which basically are entirely screen, no buttons. But I like having the buttons and didn't neccessarily want to mount somthing that looked like a smart phone on the wall. The installation was very straight forward and the included bubble level made mounting it horizontally level quite easy. The app guides you through install and as long as you know what your wires are, you shouldn't have any problem. Using it is very straight foward. Basic functionality is all supported like setting a temperature and setting a schedule. If you generally just want to do the most basic of tasks then this thermostat will definitely suffice. The information is all displayed on the screen. The screen displays both time and humidity, but alternates it - so if you want to know the humidity and it currently displays time, just wait a few second and it will switch. The associated application is also pretty useful and lets you see and control the unit from your smart phone. If you register an account you also can get notifications - for example, when the humidity is above 70% you'll get an email (at which point you can turn on the dehumidifier or AC). I personally haven't had any issues with it after a few months of use, so as far as I can tell, this unit is completely reliable - it does what I need it to do, no more and no less. The higher end models will also obviously have all the same functionality along with even more advanced functionality I'm guessing, but if you don't really want something super fancy and like the traditional appearence of this unit, then this will be more than adaquate. Also if you don't have the C-wire then you simply won't have too many options anyway. If however you really want even more smart features and want something more futuristic, then well a higher-end model might suit you more. ... show more
Reviewed in the United States on November 10, 2023 by Tom W

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