EMERSON Sensi Touch Wi-Fi Smart Thermostat with Touchscreen Color Display, Works with Alexa, Energy Star Certified, C-wire Required, ST75W , White

-------------------------------Update October 2020:--------------------------------Working flawlessly since install. I never notice any issues with it's ability to keep the temperature where I want it.---------------------------------Original Review: Aug 2020:--------------------------------This is a replacement for a Bryant/Carrier T6-NHP 2 wire thermostat used on a carrier Air Handler and a Bryant condenser unit. My problem was that the air conditioner would never stop once it started. I decided that this job is a "Do It Yourself" job due to the pandemic and since I am a retired Electrical Engineer, debugged it on my own.Not knowing much about HVAC, to get started, I had to dig into how it all works. After quite a bit of learning and diagnosing, I finally determined that the old thermostat was malfunctioning. Probably a sticky relay.The first thermostat I tried was the Honeywell RTH7600D which has a dated appearance, and had limited options for different kinds of systems. It would not work with my 2 stage heat pump. Oddly, there was no option to invert the O signal in heat pump mode. Returned.The Sensi cost more but looked more promising. It arrived with virtually no instructions. The idea is you look at web videos and go through the setup screens.Prior to installing, I like to bug out the signals to make sure they work as expected.Two problems here:1) The Sensi needs 24 VAC to work. No sign of a battery. So I ordered a 24VAC power supply.2) The wires are connected to a well designed terminal block on the back plate. No screwdriver needed here, just push to connect, just like a stereo speaker. This block is labeled however, for bench testing, when you snap the thermostat to the back plate to get power, you can access the wires only via probe points. The problem is they are not labeled. I added my own labels here and was able to bug out the unit. Note, there are two methods to bug out the thermostat.1) look for 24VAC on the various pins, while connected to the C wire with the other probe.2) Look for continuity between the Red wire RC or RH and the various output. I found out that the first method is problematic as the unit presents 24VAC to the output when it is active or not. They apparently did not install a pull down resistor on these outputs, and they float high. I consider this a design defect simply due to the confusion it could cause. I suspect it results in a number of returned units, however it is not a functional issue.When I re separated the thermostat from the back plate after debugging, I was surprised to see the LEDs still powered on in the thermostat. Apparently, there is a super-cap or maybe a non-customer battery in there somewhere to keep the unit up through small power glitches.I wired up the unit. and continued the install. Connecting to WIFI was seamless. All it asked for was to identify which network (SSID) to connect to, and the password. Nothing else.The phone app works well also. No connectivity glitches so far.The Sensi does not support the Dehumidify signal on my air handler, but it takes care of dehumidify in a similar way itself. You have good control over that also.The user can also switch on predictive programming, which causes the Sensi to arrive at your desired temperature at the specified time.You can set multiple daily schedules in the app. All pretty straight forward. It appears that you can set as many as 8 set points per day as desired. Unfortunately, the user interface is a bit rough around the edges. Once I created a specific schedule, I could not find a way to delete it. So, just be sure to modify the provided schedule for your first schedule. You can also set the unit to go fan only periodically to avoid stale air in the duct work. The unit knows outside temperature but that is through the web. It does not support the outside temperature sensors provided by my system. I would like to see the unit display the weather on the thermostat, but alas no, but is is on the phone app. It is not clear how much functionality is lost if internet connectivity is lost, but I would recommend a different thermostat if you do not have wireless internet. A nice feature is the web display can show you how many hours the system runs in each mode per day. It does not break down high cool/low cool in 2 stage heat pumps however. I would like to see that feature.There is a modest amount of control over the algorithm, but information provided about exactly what and how the unit does what is does is not to be found. Fortunately, it seems to do its job of regulating temperature in an efficient way pretty well. It is an attractive unit, but be aware that the screen starts to fade out at a 45 degree angle. I will update after I get some more experience, however so far so good.Note: Unit needs to have an internet connection for all but basic functionality.Problem: If unit goes dead, It may not be the unit. Check to make sure you still have 24VAC available. Many HVAC units shut off the 24VAC when the drain overflow switch gets triggered, such as during a drain clog.By the way, Amazon recommended to get a "Emerson F61-2663 Wall Plate for Sensi Wi-Fi Programmable Thermostat", along with this purchase. This is not needed, it is a mistake. Don't order it.

I really like being able to program and change the temperature from my phone. Works like it should. I also like being able to see the usage history.

The Sensi thermostat was so easy to install and is very attractrive. It is priced well below other industry leaders like Nest and Honeywell. I was a little reluctant at first to purchase it because I was not familiar with the name. I took a chance and glad I did.My electric utility in South Carolina just started charging $12 per KW during 3 peak hour a day. The remote access to this thermostat has allow me to set schedules and controll my heating cost very easily. I saved $45 on my January-February utility bill.A word of caution. This thermostat like most needs 2.4 GHz internet connection to setup. I only have 5 GHz but when I spoke with my internet provider they were able to assist me. I think most providers would do the same. Very simple solution, utility had me open a special app that changed my 5G router to 2.4G for 1 hour and then it reverted back to 5G. If the power fails, the thermostat reboots at 5G.I am so happy I took the chance and installed it. Fairly easy to install yourself, if you are somewhat handy with home electrical repairs. If not, call your HVAC technician.

Easy to install by following the instructions. The temperature stays within 1 degree of the set temperature. I can set it once and done.

overall, i like this product, i have 2 of them in my house. the touch screen is bright and easy to use. I dislike the service reminder for maintenance. I find usage as a better indicator of when to change the filter rather than a calendar. i could not set the usage back to zero for the reminder when i needed to change the filter. i had to create a new reminder. kinda dumb. so i set up a new reminder and it does not display my usage starting from zero. instead it shows 100% and calculating. so i can not look at it and see if i am getting close to my max usage in order when to plan my filter change in advance. and starting to lose confidence that i will get a usage reminder when it is close to the max..

I absolutely love this. It was easy to install, and it works perfectly. It’s great being able to control my thermostat and even turn the unit off using my phone wherever I am.