Sensi Smart Thermostat, 100 Years Of Expertise, Wi-Fi, Data Privacy, Programmable, Easy DIY Install, Works With Alexa, Energy Star Certified, Mobile App, ST55

(Long, but I hope worth the read) Overall, I am extremely happy with the Emerson Sensi smart thermostat. For me it was a pretty easy project, but it is important that you know what type of cooling/heating system you have prior to attempting the installation. Although the basic installation is made very simple using the Sensi app, there were some very important things not covered. I suggest you check out how to configure your Sensi on their site (Configuring Thermostat | Sensi US (emerson.com)). I’m a pretty good DIYer, but have very little experience with AC/heating systems. I was 99% sure I had a heat pump setup, but I called a local AC technician I know to confirm and am glad I did. Having installed a few smart thermostats, to include this one, he not only confirmed I had a heat pump, he also informed me I would have to go into the system settings on the thermostat and change the outside setting from ‘AC1’ to ‘HP1’. This was confirmed when I checked out the Sensi website. Armed with this information, installation went without a hitch and I was up and running in no time. Pros: - Easy to install, if you have a little DIY experience, all the information needed concerning your AC/Heating system and gather the additional information before starting. - Very easy to connect to WiFi and integrate with Google Home. Connected to my WiFi with in seconds following the instructions; when I opened my Google Home app, there was an icon to add Sensi, clicked on it and moved the thermostat to the appropriate room. I have not experienced any drop-offs or loss of the WiFi, even when I turned off my WiFi for a few hours, removed the batters or installed old, weak batteries as tests; in every case, the thermostat remained connected or automatically connected right back up in seconds with no need to go through the WiFi setup operations again. - The Sensi app, in addition to walking you through the installation, allows you to set up various cooling/heating programs to run automatically, as well as change other settings. Once added to Google Home, you can switch programs (cool, heat, auto), turn it on/off and set the temp. You can also use voice commands through Google to do this as well. - The ability to adjust the thermostat to compensate for temperature offsets. In my case, where my thermostat is located the temp registers about 3 degrees off from what it is in our master bedroom or living room. I simply adjusted the offset in the Sensi app to compensate for this and now our bedroom and living room remain closer to the set temp then they have in the past. - It can be operated manually by those less tech savvy. The controls on the face plate look and operate like those on our old ‘conventional’ one. I also like that you can lock out the manual operation from the app so that no one else can mess with the settings; like during the holidays when you have family members over who feel they can change the settings without asking .. lol. - Being able to adjust the system cycling rates. There are three settings (short, medium, and long) that can be set independently for heat, heat aux and cooling. I don’t mind having my temps vary a degree before the system cycles back on, so I have all mine set to long; during the summer, I may switch cooling to short to see how much of a difference it makes. Con: I only have one and it is the reason for my 4 rating. The instructions, at least those in the box, should include information on the additional settings that may need to be needed depending on the AC/heating system you have. At a minimum, they should inform you that you may need to make additional setting changes and where to find the instructions online.

I moved to the East coast last December. We have a six-zone boiler heating system with baseboard heaters throughout 4,200 sq. ft., on three floors (not bragging, just trying to give an idea of the size and complexity of the system). With six old-school manual thermostats spread throughout the house, it was nearly impossible to evenly regulate the heat during the cold winter, so some rooms were very cold and others too warm. I found myself constantly going up and down stairs to monitor temperatures and make sure I wasn't wasting heat or keeping areas too cold that would affect other zones. My boiler was installed in 2007, so it isn't very old and it's very efficient. However, it's a two-wire system with no C-wire, so the fact that 99.9% of "smart" thermostats on the market require a C-wire to operate was very frustrating. I stumbled across the Emerson ST55 and saw in the description that it could work either with or without a C-wire, so I called Emerson tech support to make sure before I plunked down hundreds of dollars on six thermostats that might not work. Tech support confirmed my fears that it would not work without a C-wire despite the Amazon description, so I kept hunting. Fortunately I found a YouTube review of the ST55 and the owner said he had been successfully using it with the same kind of two-wire system that I have for over two years. So I figured I'd buy one and see if it worked. Worst case, I'd send it back for a refund. The instructions inside the box clearly state that it will not work without a C-wire, but I ignored them and kept going. With only two wires it was a breeze to install. I put in the batteries, snapped it into the wall plate, downloaded the app, created an account and was ready for testing in about 15 minutes. I'm not sure if it's just my system or all boilers, but I didn't realize it doesn't turn on instantly when the thermostat temperature is raised above the existing temperature. So when I first tested it, I was bummed that it didn't work. But as I walked downstairs to the boiler, it was running! So I did some more testing, and found that there's about a 20-25 second delay between increasing the temp and the boiler kicking in. Granted it's only been a couple months since I got it, but I've played with it plenty and it's working great. Instead of a C-wire, the thermostat is powered by two AA batteries. The guy in the video said he's been using the same regular alkaline batteries for two years and they're still at 90% charge capacity, which is awesome. But I figure that even if I have to replace batteries every year, 12 AA batteries is a helluva lot cheaper than paying an electrician to rewire all six zones! On top of the six heat zones, I also have two central AC units. Thankfully those have C-wires, but I'm going to replace those thermostats with the Emerson ST55 also so that I'll have full control of all heating and cooling from one simple-to-use app. With any luck it'll go on sale on Prime Day so that I can save some money! :-) I can't speak to the Alexa integration as I don't use that functionality. But plenty of other reviewers have said it works fine. I appreciate Emerson's thoughtfulness in adding a built-in level to the back plate. I'm a stickler about things being mounted straight, so it was nice to not have to break out a level to make sure I didn't mount it crooked. As for aesthetics, the ST55 is nice. It's not too large to look obnoxious, but it has a good-sized display. And I'm not sure if it's just because I'm running it on battery, but the back light doesn't stay on constantly, so it doesn't light up a dark room at night (not too important in common areas, but important if you've got a thermostat in a bedroom). So, to make a long story short, don't believe Emerson. This thing really does work on a two-wire boiler heat system with no need for a C-wire!

~ Easy Install: No C-wire/power line needed. The phone-guided setup is excellent, which is good because there is very little paper documentation. ~ Performance: Has worked flawlessly for months. ~ No Hidden Costs: I love that there are no monthly fees for app access. ~ Remote Access: Being able to bump up the heat from my phone before I get home from a trip is a huge plus. Highly recommended for a simple, cost-effective DIY upgrade.

We've had this thermostat a month and I really like it so far. It makes me think our old thermostat wasn't actually working for a long time before it started setting itself to 85°. Since it wasn't even programmable, I knew it had to go and if I was going to upgrade I may as well go with something just a bit more...modern than a set-temp-and-it-stays-unless-you-change-it thermostat. I'm going to do pros and cons below. I do want to say, I took my old thermostat off the wall first, wrote down all the wire colors and the letter each was connected to on a piece of paper. The app removes the need for pen and paper. I just used my pen and paper to place the flags mentioned below on the correct wires. Pros: 1. This thing is super easy to install. Open the box and there are instructions for you to download the Sensi app. Once the app is downloaded it has you choose which letter slots you have wires connected to (R, RH, C, E, OB, etc.). The app then tells you how to use the flags they provide to label the wires. For example I had a wire that went into a slot labeled "R", but Sensi only had "RH" and "RC" (I think it was RC), so the app told me which R my wire needed to go in. Not having any electrical wiring experience, the app was SUPER helpful. It even had you take a picture of your wiring to save to your phone, just in case. 2. The piece that attaches to the wall has a built in level. I am super annoyed when things aren't straight on walls, so this right here, was awesome. 3. The app is really easy to set up. I just have a daytime and nighttime cycle, but I could set up all kinds of things super easily. Vacation modes, turning the AC up when I leave the house... It was great. It even walked me through how to sync the app with my Google assistant and the Samsung Smart Things app, which I didn't end up continuing to use. (See cons #1) 4. The report that tells you how long your AC is running is really helpful as well, especially since we had issues last year with it not being able to keep up. We have better insulation and updated windows and it's nice to see they are working, even when it's 99° with a heat index at 112°. (See cons #2) 5. I like that you can do things like temp and humidity offsets, have the AC turn on to help maintain proper humidity levels (we live in Florida, so this is a big thing for me), change the cycle rate (ended up choosing this one over another brand because people had issues with not being able to adjust the cycle rate on that one), and easily turn heat boost on or off. (See cons #3) Cons: 1. It doesn't work with Bixby. This is something I don't really understand, but I'm guessing they assume if you're gonna use Bixby you use Smart Things? But I can just use Google for that instead. 2. The recent usage section only shows how long the AC ran that day, not which times it ran or how long at a time it ran. It would be nice to see how long the AC was running at a time, especially in the afternoon when it gets really hot. I have not yet gotten a monthly report since I got the thermostat mid-June and it's now mid-July. Interested to see what the monthly report looks like at the end of the month. 3. Sometimes I had to change settings a couple times before they "stuck". I found after changing a setting I needed to wait a few seconds before returning to the settings menu and that helped. 4. Shortly after I got the thermostat the AC drain line clogged. This resulted in my app/thermostat constantly saying cooling was on, but the AC wasn't running. My usage for that day was like 21hrs, but I know it wasn't actually on for the majority of that. Not really a huge issue, but you won't have an accurate reading for that day. Summary: Overall, this is a really amazing unit and I have been really glad to have it. It was seriously a breeze to instakl and set up and functions well. I do wish I could connect it to Bixby without using Smart Things and I do wish I had a more detailed daily usage report, but those are very small inconveniences. I normally keep our house at 78° during the day and 77° at night and sometimes that feels cold. I would often feel hot before and wondered if our AC was not working correctly, but it would seem it was actually the thermostat. Very happy with this purchase.

Why did you pick this product vs others?: I came from a Nest Thermostat, two generations, that seemed to never be able to control my central AC system properly. I thought I was making a good decision last year switching to the Ecobee Premium Thermostat after reading all of the mostly positive reviews. It was one of the worst electronic purchases I've made, and I love technology. The one I received never seemed to measure the correct temperature or humidity, and that was with putting plumbers putting in the opening behind the plate. I had to offset both the temp and humidty of it by almost 10 degrees, which is simply unacceptable. That one was replaced, and the second was equally as bad. If you pay $250 for a device that's primary function is to read temperature and humidity accurately, it seems like basic functionality. So, I recently had to start offsetting the temp and humidity on it, and I noticed that it was never reaching the appropriate temperate on the unit all while continually running. As soon as I would turn it off, the temperature on the thermostat would drop two degrees. So, I sought out something different. Enter the Sensi Smart Thermostat. I liked what seemed like a relatively simple device all while having connected integration to Google Home. It was very easy to connect. The WiFi setup was a bit odd as it seemed like it connected, bu the app wasn't really reflecting that. After getting everything fully installed, I was able to get it all connected and registered. I have a hygrometer hanging on the wall beside the thermostat, and I also have an Air Things Air Quality monitor below it that reads both temp and humidity. Guess what - the Sensi has virtually identical readings for temp and humidity to both of them. It just simply works. Configuration and settings were easy. The app is simple and easy to use. I couldn't be happier. Don't waste your money on an Ecobee Premium thermostat, that's for sure. This one right here does the job and does it appropriately and without complication.

Exactly what I wanted: A reliable remotely controllable and monitorable thermostat. Mechanical installation was a breeze. The app walks you through the steps, where to put the wires, reminding you to label them and to take a photo of the old one "just in case". None of that we necessary for me - mine was a basic 4-wire (Y,G,W,RC) so the wires went to the same places, but it handles more complex systems including C-wire (which isn't needed for this model which is great because I don't have one). Setting up the schedule was a snap. There's an icon named "Schedule" in the app - very intuitive. And if you want to just set the temp to stay the same (like for vacation), just disable schedule and set the temp (and you can remotely put it back at comfort temp before you head home from vacation). I'm very impressed with the ease of use. WiFi connection was "mostly" easy. I had to go through the steps twice as it didn't seem to connect the first time. But hey: 2 times to get it right isn't bad. And seamless, both inside the LAN and anywhere on mobile or any other hotspot. I ran an errand that day and changed the temp while I was out and it was seamless.

The Sensi app made the thermostat easy to install. I am able to see how much energy my air conditioning is using daily. The thermostat is simple to program within the app. It’s also convenient to adjust the temperature in the app if needed. So far, it’s been a great purchase for a reasonable price.

Got this to control my new garage heater. I wanted a Wi-Fi-connected thermostat, but my installer was not aware of any available for a low-temperature environment like a garage. I found this one that goes down to 45 degrees. Works great; app is easy; includes a humidistat. The only function I would like it to have is controlling high-humidity alerts. It is fixed at 70%. My installer hard-wired it to power but said the battery needed to stay in it; otherwise, it would not work. Perhaps that's for battery backup. Otherwise, I highly recommend it and would buy again. Great value for a lot of thermostat.