Honeywell Home T9 WiFi Smart Thermostat with 1 Smart Room Sensor, Touchscreen Display, Alexa and Google Assist Everything ElseLive viewers eye icon

(10 customer reviews)

Sale Price $178.00

You Save: 12%

SAVE MONEY AND ENERGY. Adjust your ENERGY STAR certified thermostat from anywhere with your mobile device, or let your home automatically react to your schedule with Auto Home/Away Scheduling. Save even more with possible inclusion in energy saving schemes from your utility provider. (Subject to availability in area)

LIVE AND SLEEP SMARTER. Choose the temperature in a specific room, like the bedroom, to be exactly what you want it to be, to help get a better night’s sleep. Or let the Smart Room Sensors automatically detect which rooms people are in and focus comfort where it matters automatically.

AMAZING SENSOR RANGE. The battery powered Smart Room Sensors utilize unique Honeywell Home technology to deliver an efficient signal up to 200 ft range. (Could be further depending on home construction.)

MULTI-ROOM FOCUS. Don’t be forced to choose one room over another, the T9 Smart Thermostat can handle multiple rooms to focus on (requires sensors).

CONTROL IT YOUR WAY. Control the T9 using the Resideo app or through Amazon Alexa, Apple HomeKit, Google Assistant, and more.

COMPATIBLE WITH: Forced air (gas, oil or electric), hot water and steam, and heat pumps with electric backup. Does NOT work with electric baseboard heat (120-240V). C-Wire required.

DO IT YOURSELF SIMPLE INSTALL. With guided installation setup couldn’t be simpler. The included power adapter is an easy-to-install, low-voltage alternative to a C-wire, so the thermostat is compatible with most homes.

Before purchasing, check to see if this thermostat is compatible with your home and to determine if your home needs a C-wire power adapter.

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Brand: Honeywell


Honeywell Home T9 WiFi Smart Thermostat with 1 Smart Room Sensor, Touchscreen Display, Alexa and Google Assist Everything ElseLive viewers eye icon

Comfort control Welcome to ‘Just Right’

Sense the temperatures in the places that matter most with the T9 Smart Thermostat. Focus on the rooms you choose by setting a schedule — or let the sensors respond to your lifestyle, helping save energy when you leave and preparing that ideal temp for your return.

T9 Smart Thermostat with Smart Room Sensor

Honeywell Home T9 WiFi Smart Thermostat

T9's Smart Room Sensor

Smart Room Sensors, Whole home coverage

Place Smart Room Sensors around your home to see each room’s temperature and humidity. Focus on specific rooms you choose or let the sensors focus on rooms people are in.

Sensors reach up to 200 feet, spreading across the home to increase the quality of signal and data sent to the T9 thermostat.


Automatic room control

T9 Smart Thermostat Smart Room Sensors helping a couple sleep comfortably

Help everyone sleep comfortably

“Alexa, check the temperature of the bedroom.” Focus your T9 Smart Thermostat on specific rooms, such as bedrooms, so everyone can get a cozy night’s sleep.

Requires Smart Room Sensor per monitored area.

T9 Smart Thermostat cooling the house as mom comes home with the kids

Auto home and away mode

With the Resideo app, using geofencing the T9 knows when you’re coming and going, so no matter your schedule, you can always come home to comfort and save energy when you’re away.

Woman speaking to Alexa in kitchen

Your day is in your control

Control the T9 Smart Thermostat however you want. Conveniently manage it using the Resideo app, or use Amazon Alexa, Google Assistant, Apple HomeKit, Microsoft Cortana, Samsung SmartThings, and more.

Woman using the Honeywell Home app while relaxing outside

Honeywell Home app

The Honeywell Home app makes it simple to manage your devices and control home comfort. Get temperature change alerts and filter reminders, and let the T9 automatically respond to when you leave.

Woman walking past a Smart Room Sensor

People detection

Smart Room Sensors can automatically focus on occupied rooms. Advanced motion detection knows the difference between someone passing through a room or spending time there.

Controlling the T9 Smart Thermostat's room priority with the Honeywell home app

Multi-room focus

Focus on multiple rooms for comfort where it matters most. Don’t guess at the temperature in the bedroom from the hallway. Get the temp you want, where you want it—to sleep, work, focus, or unwind.

Simple setup and savings

Easily installing the T9 Smart Thermostat at home

Honeywell Home T9 WiFi Smart Thermostat Easy install

Feed your wires into the lettered ports of the wall plate, close the plate, and snap your T9 onto the wall. Then the T9 will self-configure, guiding you through a simple setup.

Woman looking at the monthly energy report from Honeywell Home on her smartphone

Monthly energy reports

Track your heating and cooling trends and get tips on reducing energy use so that you can help save on your energy bills.

Is your home compatible? Identify your home's voltage.

Is Your Home Compatible? Identify your home's voltage

Identify all the wires you see

Do you have a C-Wire?

Additional information


Product Dimensions

3.7 x 4.92 x 0.94 inches

Item Weight

1.32 pounds


Honeywell Home



Item model number

RCHT9610WFSW2003 T9


2 AA batteries required. (included)

Assembly Required


Warranty Description

2 year limited warranty.

Batteries Required?


Included Components

Thermostat, Mounting Hardware, Sensor

10 reviews for Honeywell Home T9 WiFi Smart Thermostat with 1 Smart Room Sensor, Touchscreen Display, Alexa and Google Assist Everything ElseLive viewers eye icon

  1. Jon

    I gave this product enough time before writing this review. First I would like to address the complaints people have about this thermostat. There are those who complain about the thermostat having WiFi dropouts. From my observation, it is not the fault of the unit. I have had a couple of dropouts, but the culprit was always my router. How do I know? Because my other thermostat from another manufacturer would drop out at the same time (and THAT unit is on a 2.4GHz network while my T9 is on a 5GHz network). Rebooting the router would always solve that problem.Others complain that the display is too bright and lights up the room when they are trying to sleep. I would tell those people to read the manual or to take literally 2 seconds to look it up online. Because you just go into the settings on the screen and tell it when to turn off the display completely. Mine is set to 30 seconds. Done.The smart room sensor was the real selling point of this product for me. Trying to regulate the temperature in the baby’s room when the thermostat is located in my bedroom has always been a problem in this house. Now that the sensor regulates the temperature, his room is no longer too cold at night. They allow you to regulate temperature based on temperature at the thermostat, the sensor, or an average of the two. The app to schedule temperature is also very intuitive and easy to use. It stays working. We will see for how long, but after a month it’s been great so far.I’m also using a 24VAC transformer to power this as there is no path to the C wire due to its location in the house. When my main thermostat fails (made by another company), I will replace it with a T9 like this one.

  2. Hostage67

    I’ve had the nest (gen1) for several years and have generally enjoyed it until a power outtage appears to have burned out the wifi on it. After calling the Nest support, they indicated that was a problem with Nest and they were susceptible to power outtages (at least the first gen). Given such a basic flaw in the nest design I decided to look for a different thermostat.For some time I had considered the Ecobee but had heard that while the sensors were great other areas just weren’t as user friendly. When I saw the Honeywell T9 thermostat that seemed to have everything I could want feature wise, and previous generations were generally very well thought of despite the lack of features in the earlier generations compared to the nest and Ecobee. Given the rave reviews of previous generations of Honeywell thermostats and the newly added features I decided to pick up the T9.While the Honeywell thermostat is new and I can’t tell you about the long term features (ie durability, AI, etc…) I can give you some information on the setup process…Physical Installation:This is the part that may catch the most flak from customers coming from Nest. The requirement for the “C-wire” could cause you have to install their adapter in your Air Conditioner Unit. While this isn’t actually a horribly complicated process, people who are skittish of wiring and electronics are likely to be displeased by the need for this adapter if they don’t already have a “C-wire”. In my case I was in the middle of installing the adapter when I found that my “C-wire” simply wasn’t used, I was able to simply connect my “C-wire” up without needing the adapter and I could now wire it up normally. But really, as long as you can follow some basic instructions setting up the adapter is not as scary as it may seem.Other than the requirement for the “C-wire” the physical installation is essentially the same as setting up a Nest thermostat. Simply plug the wires into the correct ports on the wall bracket and that’s really it.Once physically connected, turn the power on and the thermostat will come up and start walking you through the setup process including joining the thermostat to the wifi and adding sensors (sensors are added through the thermostat not the app). The touchscreen was very responsive and worked great. I had zero problems with the installation once I worked out my missing “C-wire” issue.App Installation:- App installation was simple (though it does require creating an account (as does the nest)).- Pairing with the thermostat was very simple and you were automatically walked through this process.- Setting a schedule was extremely simple (much better than the nest), allowing you to simply set home, away, and sleep settings instead of having to schedule daily settings (though this is still an option if you want it).- Once everything is setup you can pair your sensors with your settings so it knows which sensors to prioritize for temperature control. For example my sleep setting is paired with my master bedroom sensor, while my home settings are paired with my office, hall, and living room sensors, and my away settings are paired with all sensors.So far I would highly recommend the Honeywell T9 Thermostat. The physical installation was as easy as any other thermostat with the exception of maybe having to install the “C-wire” adapter (a one time thing, which you really can do yourself). The software was even easier than the nest to setup and use, and the sensors all appear to be working as expected. So far the Honeywell T9 has delivered on all of its promises and is the best smart thermostat I have used to date. 5/5If I were to make any recommendations for the manufacturer they would be as follows…- remove the requirement for the “C-wire”, this is not required by nest and installing the adapter may be more than some people are willing to tackle even though it is really something that can be self-installed.- add the option to add sensors via the app instead of requiring that they be added through the thermostat. This is a minor gripe, but there is no reason this functionality couldn’t be added to the application for ease of use.

  3. JNH

    I have used Honeywell Programmable Thermostats for years and have been watching this one trying to come up with an excuse to purchase it. I finally just ordered it.Our Thermostat is in the Kitchen and it works well during the day, but at night we prefer to control off of our Master Bedroom. The programming was easy and it controls our bedroom at night.Yes, that means that the Kitchen temperature may be higher or lower than we want normally, but the place where we are is comfortable and that’s what HVAC is all about.I’ve been thinking about adding another remote temperature transmitter for another room and possibly controlling off of it in the later afternoon.

  4. Ashley

    Our master bedroom is noticeably a few degrees warmer than the rest of the house. This makes sleeping uncomfortable. We had the Honeywell T4 thermostat and purchased this T9. Luckily that made installation a breeze! All we had to do was remove the current thermostat from the wall and pop the new one on. All the wiring was exactly the same so we didn’t even touch it. Easy!Setup was easy too. Easily connected to wifi and the app. Quick connection to the sensor which we placed in our master bedroom. We prioritized this sensor on the thermostat so our bedroom would cool down. We’ve only had it for one day and it’s already working so well! It’s a noticeable difference. We have a thermometer in our room to check the accuracy of the sensor reading too. Very happy!To top it off, we purchased the ‘damaged box’ version, which was significantly cheaper. I was a little nervous that the thermostat would be damaged or wouldn’t work properly, but it’s perfect!Overall very happy and would recommend.

  5. D. Sanderson

    (this review is long but detailed – hope it helps someone)I hesitate to review this thermostat too soon, as I bought a Honeywell RTH9585WF1004 ($200) 14 months ago, gave it a good review, then 13 months later it completely lost any accuracy of the actual temperature – and why I now have the T9. I also hesitated to continue with Honeywell, as the past 2 wi-fi thermostats from Honeywell were horrible (TH9320WF, returned within one month, and the RTH9585, worked for 13 months) – but I didn’t like the other brands available. The T9 is brand new, and the remote sensors sounded awesome for my house – 2 story, 1 AC unit, terrible air circulation, temp varies between floors/rooms.INSTALL: I removed the inaccurate Honeywell RTH9585, and installed the T9 according to the very basic install instructions. I had one issue with installation which was my own fault – set the wrong type of HVAC unit in Setup, so the AC wouldn’t turn on – then I caught my mistake. I’m still not entirely sure I have the correct type selected, as the T9 indicates my heat pump is 2-stage and I don’t believe it is…I’ll find out in Nov when I need heat in Arizona.SMART ROOM SENSORS: Bought a total of 4 Smart Room Sensors, 2 for upstairs (one in M Bed) and 2 for down. After installing the Base unit, went to Settings and simply followed the unit’s displayed procedure for installing/naming the Smart Room Sensors (place one sensor, return to the Base, name it, then go on to the next sensor).SCHEDULING: This section was really easy setting up a “5+2” day schedule which allows for multiple Away/Stay cycles (vs the usual 2 On/Off, On/Off cycles on previous thermostats). It was also really easy choosing which Sensors to use in the programming. Example: WAKE time, I’m in the Loft on the computer, so that’s the Sensor that the Temperature is based on. AWAY time is mid afternoon (Peak Pricing) so the temp is set higher. HOME is at evening (when Peak Pricing ends), I’m always downstairs in the Kitchen or Family Room, so the Temperature is based on those 2 Sensors, SLEEP at night the Temperature is based on the Sensor in the M Bed. More cycles can be added – I’m not sure if they can be named differently. I have the sensors set for times, but they can be used as motion detectors to detect Activity, making them active. If multiple sensors (that you selected) detect activity, the temperature is based on the average of the Active sensors. I don’t know what happens if a sensor senses brief activity (like grabbing something from the kitchen then leaving that room, example) or what happens once one goes to bed, thus there is NO activity. For me, using set times is better. Geofencing is also an option but not one I need/use. It detects (via your cellphone) when you’re in/out of range and adjusts the temp based on that. (how it works with a family, I don’t know) I’m honestly not gone for more than several hours at a time, plus I have a zoo so can’t let the house get too warm/cold.HONEYWELL HOME APP (Android): After a week using the Schedule I’d set, it needed a bit of tweaking with some temp changes and changes in renaming/moving a Sensor. I had already installed the Honeywell Home App on my phone but hadn’t really messed with it – so I did my “tweaking” of the T9 programming through the App, not the Base unit. It was a bit confusing at first (it’s not super intuitive) but, once I got the layout of the App, I was able to make temp changes, move a Sensor, rename a Sensor, adjust some minor details. Using the App (once I got the hang of it) was easier to program the T9 than using the Base unit – I was able to do it sitting down in another room vs standing, hunched over at the Base unit. The App can’t be used for the Initial Setup of the Base unit, obviously.CONS: 1) Wi-Fi is supposed to be 2.4Gh or 5Gh. I tried to set the Base to my 5Gh signal…it found the signal but would not connect to it – I got an error message and told to contact Honeywell Support. I didn’t want to mess with that (I’ve read it needs a Firmware update – I just haven’t checked if that’s true) so it’s set to the 2.4Gh signal. Honestly, don’t know what diff it makes, why would a thermostat need a faster signal? Only reason I can think of is that my phone is set to the 5Gh and the T9 to 2.4Gh – BUT I was still able to reprogram the Base using the App, so I don’t know.2) The instruction manual is very basic; it gives very brief install instructions, the pictures of the wiring could be a little bigger/clearer. There are no instructions for installing/setting up the Sensors (the Sensor box has a very brief install/program/pairing instruction). That’s all described (fairly well) on the Base units display.3) The Honeywell site has no more instructions than what’s in the box. There are some VERY short (~2min) videos on how-to for a few basic things but I didn’t watch them. An Online User/Help Forum would be a great addition, I’m sure most people have the same basic questions and some need more detailed instructions – forums are super helpful. It’s possible they do have a Forum somewhere but I didn’t see one or a link.4) Alexa is supposed to work with the T9…and it does (once you add the Skill through Alexa – make sure to remove the app/skill for older thermostats) but it’s rather confusing. The Alexa App did a search for new items and it found the T9 Base, as well as the 4 Sensors. I can use really basic commands BUT you have to use the name you gave to the Base and/or Sensors…I said, “Alexa, raise the temperature 1 degree” and it replied, “I found multiple items…”. I haven’t explored it enough to know whether I can say, “Raise the temperature of Kitchen 1 degree” or so on for the other Sensors – and again, Honeywell has NO online instructions for using Alexa or other voice apps. On the other hand, for now I have the programming/scheduling JUST right for all rooms and various times of day, so I’ve not needed to change it since my tweak.5) The price is a bit high. Over $300 for the T9 and 4 Sensors (especially since I spent $200 last year for the previous Honeywell unit). So far, having the house a LOT more comfortable and NOT having to be changing the thermostat setting throughout the day, it seems to be worth the money.6) The sensors are applied using double-sided tape. This is both a pro and a con. Even after cleaning the wall where one sensor was going, the sensor fell off the wall 5′ to the tile floor. The tape is nice for not having to use screws and in that I decided to move one of the sensors, but I’d feel better using a screw.PROS: 1) It’s only been 2 weeks, but the T9 is working great and it’s nice having various rooms of the house at slightly different temps at different times.2) Easy installation. For my HVAC unit (12 yo heat pump) the wiring was simple enough and I already have the C-wire. The T9 does come with an adapter for homes without a C-wire, I don’t know how easy it is to use.3) The Setup was actually very easy to use (aside from the 5Gh Wi-Fi not working).4) The Honeywell Home App is also easy to use, once one understands the interface.5) Multiple Home/Away cycles. I’m generally home all day so I don’t need more than the usual 2 On/Off, On/Off cycles but I’m sure the additional cycles are convenient for some households.Final thoughts: I’ve read several other reviews complaining of needed firmware update and a hassle of needing to use 2 Wi-Fi phones to do the update. I couldn’t get the 5Gh to function, but the 2.4Gh works just fine. I guess some people have their Wi-Fi set up so there aren’t 2 separate signals? I’m not sure – but I might find out someday if I ever decide I really want the 5Gh signal. I’ve also read people complaining about the App not working. I’ve had no issue at all with the app. Also, I’ve seen people state that if the power goes out, the entire T9 configuration and schedule is lost. I haven’t had power issues, I just hope that’s not the case. One would think that the settings are saved either at Honeywell Cloud or on the phone, if not the unit itself (though it doesn’t use batteries). I hated the previous Honeywell Wi-Fi thermostat, but it never lost it’s programming so I can’t comment. In my experience so far, even though the included instructions were very basic, the setup for the T9 was straightforward and easy to comprehend using the Base unit’s displayed instructions. I only hope that I didn’t spend $300+ on a Honeywell Thermostat that will only last 13 months, as my last $200 unit did. So far, I love it.

  6. J. Henderson

    I noticed our 2012 builder-grade Honeywell T6 thermostats display temperature was not accurate anymore, and our house was becoming drafty for a well-insulated newer home. I thought I would upgrade to the T9 but was concerned about the many poor reviews on Honeywell and Amazon (e.g., doesn’t work with gas, terrible app, broke this or that reviews). So I began to wonder if my system was even compatible and if I would mess it up by being cheap and installing it myself. If you are like me, I hope this helps!Yesterday I installed 2 thermostats for electric cooling & gas heat and 4 sensors myself. I was surprised by how easy it was. I had 5 wires, the 5th being a variable speed fan control which I investigated to figure out if the T9 would work on a variable speed system. Yes, it does and the app has a circulate option so the air is moving beyond just when the system is changing temps.The T9 was easy to set up on the wall, and then I completed the setup options/schedules in the app…just because it was easier. The thermostat and sensors each connected quickly to my EERO mesh system on 2.4. I tested the cooling and heating and each worked fine. Given its the TX summer I placed it on cool vs auto as I didn’t want the heat to engage at all to keep the temperature exactly at 75 if it dropped lower at night. At night in the sleep schedule, I set the app to use the master bedroom sensor as the temperature point vs an average of the thermostat and sensors. A sensor can only be paired to one of the thermostats but many can be paired to ‘average’ out the house temperature. Or select one sensor to use as the main focal point when in use occasionally (say a master bedroom or media room).I have not tried geofencing or Alexa as that is not as important to me.Net, don’t read the older reviews. If your system is 10 years old you are probably fine upgrading. I’d say more issues may be in older systems or special setups for particular regions. They must have listened to the comments on the app. It was easy and intuitive.

  7. Zach Mikolajczyk

    I waited about a month to do this review because of some of the negative reviews. A lot of people are/were having issues with this unit but for me it was a piece of cake. I didnt have a C wire and didnt want to use the bulky adapter( although awesome really awesome they created an adapter to give you a common if you dont have one) instead I just ran a new 5/18 wire to replace the 3/18 that was there originally . Once I got that out of the way I downloaded the app, turned the unit on and went thru the installation on screen, set up an account on my phone and to be honest things got a lil weird here. I made an account on my phone and started linking the two. The thermostat linked to my account but my phone kept saying there was an error. I wasnt hard pressed on needing the app right away so just stopped trying and 2 days went by and noticed a new app on my apple watch. Clicked on it and bam it was the thermostat, I was like woah how cool. Opened the app on my phone and everything works flawlessly. One thing I will note is only link the thermostat to your 2.4ghz network not 5ghz. It might do it but they don’t recommend it. As far as operation its super easy and really intuitive. I showed my 93 y/o grandmother how to operate it with ease. Really nice scheduling. Really can just set it and forget it. Also I like that the screen stays lit even at night its not to bright ( you can change its daytime brightness, and night time brightness in the menu) its a perfect hallway night light. I have 2 external thermostats linked to it as well, they to were super easy to set up. Overall great product. Next im going to work on getting it to work with Alexa (havent even tried yet) and seeing how the Geofencing works. Overall great buy would definitely recommend

  8. Jonno N.Jonno N.

    I shopped my smart thermostat for a long time and came to a few conclusions:1. All the so-called “AI” features on Google Nest and other smart thermostats are just a gimmick. The reviews on those products prove this, you can find an endless stream of comments saying it “learns” to do the wrong thing over time. One need only watch the 1984 classic “The Terminator” to know why we can’t trust the robots with control over our most precious technology. These features are supposed to make your life easier by not having to set a schedule. I found the schedule feature to be incredibly simple and intuitive on this Honeywell device. I included a picture of the interface. I programmed it in about 3 minutes from my phone.2. The other smart thermostats are not pleasing to the eye. They may look good on modern homes but in a somewhat plain or modest home they stand out and not in a good way. I needed a simple white thermostat with an easy to read display for anyone at any height level. The Honeywell is simple and uses all the device space as one huge screen. It’s like the Tesla of thermostats in terms of screen size and display information at a glance.3. This thermostat is able to be locked down such as in a rental or AirBNB. Meaning the settings can’t be modified other than adjusting the temperature up and down. This is basically a simple mode for the whole family or for your renters. They need to be able to adjust the temperature but they don’t need anything more than that. It’s great for family uses but if you’re a professional property manager there is an upgraded version that can be operated in bulk. I like to just buy the best on the market so I shopped that option and decided that I don’t need those features so this is the best on the market for residential use.4. I used an installation service with OnTech. I learned about them from getting my Ring Doorbell installed with them. They gladly installed this device too and it works really well. They said the installation was very standard and nothing special on my particular house and hardware. I would really suggest doing this installation if they service your area. It was cheaper than hiring a professional electrician and the workers they sent were more professional and knowledgeable on smart home installations than a typical electrician.5. The app is really easy to use. I set up an account then logged in wife’s phone with the same account and we can both manage the temp. We don’t have to because the schedule works great but sometimes it’s nice to adjust it from the couch without having to get up.6. It’s all about sensors. Sensors sensors sensors sensors. Did I mention sensors? None of the other smart thermostats have room sensors. Their supposed smart features just learn from your personal behavior not from any real world information. So if your family gets up and adjusts the thermostat randomly one day it learns that behavior. Very useless behavior. This actually reports real time temperature and activity information from your room sensors and adjusts the heat and air conditioning based on that data. For example you can set the priority to “active rooms” and it will prioritize rooms that show activity. Or you can use GPS settings to prioritize when you’re home and not head the house when you’re away. Lots more actual smart features on this device than the competition. These features are not gimmicks they are real features you can rely on.I wrote this review because I spent a lot of time researching and thinking about the options. I hope it helps a few people make the decision. Please hit the “helpful” button for the next person that is walking this path and might need a little help.


    So far so good. I really like this Honeywell T9 Thermostat. It has scheduling, occupancy sensors, remote sensor, and geofencing. You’re bound to find a mode or combination of modes that will work for you. Pretty decent app to go along with it. They need to change the unit and app to display the remote sensors name if you are using your remote sensor. As of now it shows the main units name while using either the main unit or the remote sensor. Minor thing but hopefully they change that too reflect actual sensor being used.

  10. Edward F. HartEdward F. Hart

    I like this thermostat. The thermostat for the sleeping side of the home is in a hallway. When bedroom doors are closed, there is inadequate airflow to give temperature feedback to the thermostat, leading to long AC cycles and inconsistent bedroom temperature fluxuations. The T9 nicely solves the problem by letting us have a remote thermostat in one of the bedrooms to take over control and transmit the room situation to the main thermostat. It works quite well.I am above average around home systems, so if you plan to install yourself, know this: In order to have full control of the HVAC system, the thermostat needs to have access to the “C” (Common) connection on the indoor furnace or air handler. In my case, the connection was not available at the wall thermostat location. This is because the mechanical thermostat the T9 replaced did not need access to the “C” connection. Lucky for me, the installer many years ago had used standard thermostat wiring. This wiring has the blue “C” wire. In my case, it was simple to connect the blue wire to the “C” terminal on the furnace, then connect the other end to the thermostat. Bingo. Worked instantly.My wife objected to how bright the display is, but I simply went into the menu and reduce the brightness to the level you see in the photos. There is peace in the family!

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