Smart HVAC Ductless Mini-Stat

Finally, a Smart Thermostat for Ductless Tech

  • January 3, 2020
  • By MR COOL

Max out on comfort, affordability, and energy savings with the new Smart HVAC Ductless Mini-Stat for MRCOOL ductless air conditioners and heat pumps. You’ll have the ability to lower your energy bills, get cleaner air, and customize the comfort of each heating and cooling zone in your home or office from anywhere, any time. 

This easy-to-use comfort tool seamlessly links up with your smart device of choice. It gives you the luxury of taking complete control over each room’s temperature, humidity, mode, fan speed, and swing position from any location, inside or outside, via simple touchscreen controls.

An Affordable Smart Thermostat for Ductless

Comfort and convenience doesn’t have to come at a high cost. Priced to fit your budget and paired with a free application available for both Apple and Android devices, this updated tool integrates with your smartphone and/or other smart home devices for managing the heating and cooling of your home or office is designed with affordability in mind. 

Combine the amazing features of the free smartphone app with your energy savings, and you’ll have a real bargain that can make a difference each year. 

Simple & Easy to Use

The MRCOOL Smart HVAC Ductless Mini-Stat turns your already smart MRCOOL ductless air conditioner or heat pump into an even smarter and more versatile comfort tool that is easily adjusted and tracked throughout the day using the smartphone app. Thanks to a 5V adapter in the Wi-Fi smart controller box, you can power up this thermostat from any location inside your home or office. In order to get the most accurate reading of your room temperature, make sure to set up your Mini-Stat within a line of sight of the unit, to ensure it maintains an infrared connection.

The MRCOOL Smart HVAC Ductless Mini-Stat has a simple menu of options to choose from in order to fully customize your heating and cooling settings. Since the Smart HVAC Ductless Mini-Stat is linked through your smartphone, that means you can adjust temperatures not only from inside, but also while you’re traveling or located anywhere else outside of your home or office. This global control feature ensures that you can change your heat and air conditioning settings from any location around the world. 

Simplify Your Comfort Schedule

With the customization options available through smart scheduling, you can set your temperature dependent on your personal preferences and daily routine. Keep your bedroom cool while you sleep and warm by the time you wake up. Adjust your heating and cooling settings only once and your routine will be set.

If you’d rather keep temperature scheduling to a minimum, geo-fencing makes it possible to automatically adjust your thermostat when you leave the premises and again as soon as you arrive. Like daily scheduling, the geo-fencing feature is a one-time process. Make your customization at the beginning of set up and there’s no need to revisit unless your preferences change. 

Cleaner, Customized Air Conditioning and Heating Control

There’s a good chance you’re not the only person who has a hard time remembering to change the air filter in your home or office. Neglecting your air filter leads to increased dust, allergens, and impurities in your air. With a simple tap on your smartphone, you can monitor the status of your air filter and dramatically improve your air quality without the need for reminders and eliminate the consequences of forgetting.

Keep Your Thermostat’s Heating and Cooling in the Zone

The Smart HVAC Ductless Mini-Stat offers temperature customization not only by your schedule but also from room to room. With each zone having its specific heating and cooling ranges set, you can ensure that those cooking in the kitchen stay cool, while those lounging in the living room keep cozy. Throughout your home or office, you can manage all your home air comfort requirements with a single touch, ensuring everyone in every room stays comfortable. 

Monitor Your Energy Usage and Save

If you aren’t sure about what temperature settings are the most optimal and cost-effective for your home or office, with the MRCOOL Smart HVAC Ductless Mini-Stat app, you can track your energy usage patterns and statistics in order to keep an eye on any energy “leaks” in your heating and cooling usage. Check out your timeline of actions feature and take note of who is using your system, at what settings and when. You can then use this information to manage how you set up your heating and cooling schedule throughout each season of the year. 

Some engineers estimate that a smart HVAC thermostat control system can lower your energy bills by as much as 25%. Over time, MRCOOL’s innovative smart system will create a difference you can feel in both your home and your wallet.  

What You Get with the Smart HVAC Ductless Mini-Stat Wi-Fi AC Controller from MRCOOL 

When you purchase a Smart HVAC Ductless Mini-Stat, you’ll receive a one year limited warranty. Each box comes with a table stand, wall mounting kit, a 5V DC USB adapter, a micro USB cable, and a user manual for DIY setup instructions.The Mini-Stat does not, however, include the required Wi-Fi router and a working internet connection. Please be sure to have that prior to purchase. 

If using a smart device, the free MRCOOL Smart HVAC Ductless Mini-Stat app will walk you through the setup process and help you get the most out of your various settings and options. If you aren’t using a smart device, don’t worry, the user manual can do that, too.

Get One for Yourself!

Now is the time to max out on your energy savings and the comfort of your home with the new Smart HVAC Ductless Mini-Stat from MRCOOL. Once you make the switch, you’ll wonder why you waited so long to take advantage of this simple way to keep your home at the perfect temperature from anywhere at any time.

118 thoughts on “Finally, a Smart Thermostat for Ductless Tech”

  1. Hi, does the mini stat take over the internal thermometer that would normally control a mrcool diy unit, such that it’s a more accurate room temp reading than the one inside the unit? I already have the new generation wifi controller inside the unit, or is this redundant? Thanks for any guidance.

      1. What? That is wild. Why would this be developed at all if it’s not even going to be compatible with all Mr Cool products?

        1. Conventional central HVAC systems and ductless mini-splits operate very differently. Making a single thermostat that can work with both types of systems is more challenging than it might seem.

  2. Does this turn off the inside unit when the desired temperature is reached? And turn on the unit when the temperature is out of range again?

    1. You can control the unit as you would with a conventional thermostat. Setting the temperature on the Mini-Stat will set the temperature by which the mini-split functions.

      1. Does the wall thermostat turn the fan of the wall unit off when it reaches the set temperature? Currently, the fan continues to run when you hit the desired temperature and turns the compressor on and off when the desired temp is reached. So does the inside fan continue to circulate air when you reach temperature. We want to leave the heat set at our cabin to turn on when the temperature falls below 50 but don’t want to leave the fan circulating air for 3 weeks before heat is needed.

        1. The fan does not stop while the unit is on. I would recommend you use the Freeze Protection mode for your cabin during periods in which you are not present.

  3. I think I speak for all of here when I ask for more clarification on if this unit is purchased if it will help give a more accurate reading of the actual room temp. For example – I typically run my mini split in Auto mode at like 72 degrees. My unit will run constantly and eventually drop the room temp far below 72 degrees. When I look at the app – it shows the room temp as above 72 degrees until I change it to heat mode – which it then updates the room temp and shows a new reading (far below 72 degrees). I purchased this unit in hopes that it would maintain a room temp and after about 2 months of use I can confidently say it is impossible to do just that. I would be more than willing to purchase this if – it sends the unit a more accurate reading more regularly than the internal probe.

    1. The fan runs constantly, but the compressor does not. You can control the operating temperature with the Mini-Stat, but the unit relies on its own internal thermometer.

      However, you shouldn’t be seeing the kind of performance that you’re reporting. There may be a problem somewhere, either with the app or your system. Please give us a call at 270-366-0457 to speak with tech support.

      1. I am having the same exact problem. Every time I a free, I try to call but it always makes me leave a message. I always get a call back the next day when I am at work and cannot answer.

  4. Does this replace the internal thermostat. My Mr Cool Primere is horrable at keeping a constant temperature.

  5. I simply want one thing out of my unit:

    It to maintain a temperature range. To have a max and minimum temperatures.

    Meaning, if I had the heat set at 65 and the cool set at 75, it will cool the room when it gets above 75 and heat when it gets below 65.

    I have the 18k btu Advantage 3rd Gen with smart controller. What do I need to do to be able to have the unit maintain a temporary range?

  6. So to be clear the mini-split remote thermostat is really just a controller and display, but does not have an actual thermometer/thermostat on board. It merely is a remote control with display and the blower unit just uses it existing onboard thermostat to operate the unit, thus improving conscience but does not actually control the units operation.

    1. It is another control tool. Customer feedback indicated that some people wanted a more traditional looking thermostat for their mini-split. Which is why we came out with the MiniStat.

  7. Will the Mr Cool unit turn on or off by itself if a desired temperature is set like a traditional thermostat? I have a sunroom and we want to keep the door open, but do not wan to run the unit 24 hrs/day; it would be nice if it was able to function like a traditional AC unit. Is it built to run 24/7? I am not sure the Auto function is the exact substitute. Thanks.

    1. You can set the unit on Cooling mode and then a set temperature. It would turn the compressor on or off as necessary to maintain temperature.

  8. Will the Mini-Stat let me set the target humidity for my room? I want to make the humidity control in my garage automatic so that I can bring my dehumidifier back in the house. The current SmartHVAC app only lets me turn dry mode on or off or schedule it – there is no humidistat functionality like I was hoping, so I’ve been using both appliances…

  9. We have one of your Wifi DIY mini splits. Our one complaint is that it continually says it is offline, thereby not allowing me to control it remotely. If I purchase and install this thermostat, will that eliminate the problem or will I again get the recurring “OFFLINE” message?

    1. You should be able to turn the unit on or off from the app. The Mini-Stat should not affect this functionality.

  10. I seem to have a temperature variation issue on my Mr Cool. I have my unit mounted about 18-24″ from a 10′ ceiling. The problem I have is when I set the cool tempeture to 75′ it will cool my room off to about 69 or 70 degrees. There seems to be a 5-6 degree difference. Would a wall thermostat help with this issue?

    1. It might, but this could also indicate an issue with the unit itself. Give us a call at 270-366-0457 so we can get to the root of the problem.

          1. Maybe we are seeing a trend here ? I came here after doing a google search on MRcool thermostat not working.. I purchased the 12k unit from you guys for the master bedroom.. I set it to 76 cool low fan setting…. It will cool down to 66 degrees and never shut off..
            I do not mind buying an after market and or better thermostat for this unit if the large swings.. otherwise very very happy overall.. Please let me know.. I tried calling and could no get through.. ended call after 30min.

          2. Sorry you couldn’t reach us. We’re looking into the thermostat issue, but having trouble replicating it. Could your unit accidentally have been set to Dry Mode?

    2. I’m having the exact same issue.. It’s rather annoying. I’ll set it to 74 and it cools my room to around 68 and then doesn’t turn back on until around 75. Way too much of a swing. I’ve tried calling several times and wasn’t able to get much help. Can someone please help me with this?

      1. I had the same thing happening. For the last couple of days I’ve been using the Follow Me function on the remote, and this seems to level out the temperature swings.

        1. I had no idea what the follow me function was until “Jimmy” above mentioned it.. Im so very glad he did… This seemed to have helped my issue quite a bit.. Did not fix it completely , but makes it a heck of a lot better..

      1. Pressing the temp buton down did not change a thing on my display (12k unit) . However, the actual button on the remote labeled “LED” does turn the display on the unit on and off.

  11. I have a question on temperature range. I see that the DIY 3rd Gen remote lists an operation setting range for the remote of 62F to 86F. From looking at the specs, it seems as if the DIY 3rd Gen could heat at lower temps. The setting range for the Mini Stat is 40F to 90F. Does the Mini Stat allow the DIY 3rd Gen to operate in this 40F to 90F range? Or is it still restricted to 62F to 86F? I want to install a DIY 3rd Gen in my garage but keeping it at 62F all winter would be overkill. Being able to set it within 40F to 50F range would be much better.

    1. The Mini Stat does not change the set temperature. However, for your garage you can use the Freeze Protection setting to keep the temperature low, but safely above freezing to protect your property.

  12. I am having the same issue as several people mentioned above with a lack of temperature control. I called Mr cool, asked IWAE where I bought the unit nobody has been able to help. I have a 12k DIY Mr Cool Mini split. The issue is I will set the unit anywhere between 76-78 degrees and it always cools the room down to 69 or colder. I have tried trimming the plastic tube over the temperature sensor, using the follow me function on the remote, adjusting the temperature calibration, and none of those has helped. Can I add this mini stat to fix my issue?

    Thank You!

    1. Hi, Mike. We’re not sure the Mini Stat would help with this issue. We have had a few reports about this kind of activity, and we are currently investigating the cause. A tech team member will be reaching out to you soon.

      1. I also have this same issue. I’m doing my best to track the usage on my system and some times i look at the unit and it ran for a crazy amount of time. (weirdly enough when it’s colder out and the unit really shouldnt have to run) I was able to make it better by using the comfy feature and have it turn the unit off if it falls below a set temperature but if comfy is off it will just run all day if i let it and get the temp in the room super low.

          1. Hi I have tried contacting tech support a few times but can’t get anyone on the phone. I would really appreciate some help.

            Thank you!

          2. We apologize for this inconvenience. We’re currently seeing an extremely high level of calls, but we’re trying our hardest to get to everyone as soon as we can. We do also have an email option available here to provide another mode of contact.

    1. Hi John did you end up finding an answer to your issue? I have the same problem and can’t seem to get it resolved…

    1. I forgot to add: can I replace my current home, central HVAC system with one of these so I can control my three ceiling cassettes AND my home HVAC system together?

      1. I have three Mr Cool Olympus ceiling cassettes, have connected the MiniStat to one, and I am having the same issues others are noting. The temperature range is extremely wide. When it turns on the one unit, the other units also kick on, despite the fact they are controlled by wired controllers.

  13. I am having the same temperature control problem. I set the thermostat to 80 and it still cools to 71. The follow-me feature does not make a difference.

  14. I have a MrCool 36k Olympus mini split condenser with 4, Oasis evaporator units. Each oasis evaporator has a smart usb installed and linked to my WiFi router which has an excellent signal. Problem is, the evaporator temp sensors are very inaccurate from actual room temp. I’m constantly re-calibrating room temp. Also, in heat-pump mode the evaporator doesn’t shy off even when room temp is 10 deg above temp setting. It very frustrating. Can you guys help?

  15. In the winter my unit reads 80 degrees when the room is 60 degrees so it thinks it doesn’t have to do anything. Will this correct the issue?

    1. I had the same issue and left a message to tech support. They called me back and provided the following options.
      – Follow Me on the remote will take the room temperature from the remote and send a signal to the unit every 3 minutes on the current temp. This is an immediate fix when you’re close to the remote. He mentioned if all else fails use the remote for a little more accuracy on the temperature.
      – Go to Device Preference on the app and reset and/or play with the temperature calibration.
      – Something that I did just in case was move the temperature sensor in the unit so it’s poking out of the top of the unit a little. The technician said it might work since I didn’t have high vaulted ceilings. I read in previous comments someone cut a little bit of the plastic tubing but I plan to cut the tubing as a last resort.
      -Factory reset/reboot the system if you haven’t already.

      The temperature sensor isn’t 100% accurate so it might be more of a component quality Mr Cool will need to investigate. In addition, although the app is more user friendly then their competitors it definitely has a bit of delay and sometimes the app and remote both say different things. Hopefully, they upgrade their software system soon.

      1. Im on a 4th gen unit and like others came here wirh this issue. For me follow me helped but that also is not 100%. Not sure i would have purchased knowing this problem.

  16. Is there a more simple thermostat? Or will this one operate without wifi? I dont have internet, but do have a smartphone. I just need to be able to schedule temps, either with my phone or manually. Thank you

    1. The Mini-Stat can operate without Wi-Fi, and you can set a schedule on it. We do have an app, the Smart HVAC app, but it requires Wi-Fi to control the system.

  17. The thermostat circuitry for AC is not working properly. You basically have to operate the unit manually (turning the temperature setting way up to turn the compressor off) regardless of using the “follow me” option or not.

  18. I agree the temp sensing is off. I recently installed a new system and I find it interesting even in ‘follow me” mode the temp on the thermostat doesn’t match the iPhone app as the temp in the room. They can easily be 10 degrees off. I don’t know where that app temp is coming from I suspect the unit itself instead of the remote thermostat. If you use follow me they should match even if it’s off a few degrees fro m the head unit.

  19. I installed a Mr Cool 18k BTU unit, and will the use of a thermostat cut the unit on and off based on the desired temperature set on the thermostat by the user?

    1. A traditional thermostat is not compatible with a ductless mini-split like the DIY 18k, but you could use our Mini-Stat for the same functionality.

  20. You temp sensor for my gen3 18k is horribly inaccurate. Bought the mini stat hoping it would help maintain a constant temp and it’s just as bad as the built in senor on the air handler.

    I set the temp for 80f and it cools to 76. You guys realize that having accurate control over the temp is crucial?

  21. Ok – I have a question and it seems like it’s being danced around in the answers above so I’m hopefully going to ask it directly, and receive a direct answer.

    If I connect the Mr. Cool Mini-Stat to my Mr. Cool Mini-Split system – will it heat/cool the room based on the temperature read at the mini-stat in the middle of the room in the heart of the living space, or will it heat/cool the room based on the temperature read at the actual indoor unit 6 inches from the ceiling?

    I need to understand the answer to this direct question before i spend $90 on this Mini Stat

  22. I think it’s pretty telling how many people are here looking to solve the same problem. I have the 4 zone unit and while I love the system the difference between the temperature the unit sees and the actual room temperature is insane, sometimes in the double digits. I highly doubt there is anything wrong with my system since all 4 heads do it occasionally. We have all 9 or 10′ ceilings, so I understand there is a temperature difference between the bottom of the room and near the top where the condenser is actually located but it seems like there’s more to it than just that. It does seem like the problem is best dealt with by leaving all fans on at least medium, never on low or auto, so the sensor gets adequate fresh air.

    What’s frustrating about this is that I could easily fix this problem with my home automation system however Mr Cool seems to have intentionally locked down their wifi adapter from local access. A frustrating finding when the product I have is marketed towards DIYers.

    1. What did Mr. Cool support help with in thi case, Tim? Anything about unlocking wifi protocols or methods of control for the DIY automation community?

  23. I have 3rd gen indoor units connected to a 24k and a 36k condenser(2*18). All the indoor units report wildly inacurate temperatures and vastly different from the mini stat. Each unit came with a mini stat a remote and wifi dongle. I am having the same variation temp issues as everyone above. An article should be posted on how to mitigate this since everyone is having the same issue. Call support is not an acceptable solution when everyone is having this issue. Post possible solutions and you would save hundreds of hours of phone time.

    For those thinking about getting a mini stat or wifi dongle DONT it will NOT provide any added functionality.

    Comfy mode runs my units non stop (24h), follow me does not help at all and calibration is only valid for an hour or so before the temperatures are off. The unit needs to read the temp on the mini stat and turn on or off according to that and not it’s internal thermostat which seems to be junk.

    I will post an update when/if i find a solution to this issue. I have 10000$ worth of useless air handlers in the meantime. And i would urge MrCool to contact me instead of replying with “Call support”.

    1. We apologize for this. I can send your email address to the service team manager, but in the meantime, we would recommend that you call us at 270-366-0457 in case you are able to reach us before we reach you.

  24. Like everyone else here, I have the same issue. In both heating and cooling modes, the unit must be set to about 5 Deg C higher than I want the room to be. I installed a small thermometer on top of the unit and found that the unit does reasonably control the ceiling temperature to the requested setpoint. I also notice that in the summer, the unit will make the middle of the room cooler and cooler throughout the day and I assume that this is because of the attic warming up and making the differential between ceiling and room temperature even greater than 5 Deg C.

    Based on this, I am able to control the unit within reason but it’s not ideal. Follow me on the remote control does nothing, I’m not sure why.

    My $0.02.

  25. Hi,

    I would like to control dry mode by temperature. Is it possible. Do you have a secret setting to turn off the fan in cool mode when the compressor drop. I have 3 1 ton Mr. cools with wifi.

  26. I installed the 18K DIY a few months ago. So for it works great and its very efficient ( haven’t tried heat mode since its been summer), but I came to the site as well to find many many people have had the same issue I’m having with the wide temp ranges whether its the wall or remote thermostat with a temp swing of 5 to 6 degrees. I understand the unit needs some kind of variance in temp since it varies the fan and cool/heat output like the auto climate on you car or truck, but is there a software update or upgraded thermostat that will shorten this range to maybe say 2-3 degrees? Or have an option you can adjust the swing in temp range? I don’t have Wifi, but I can bluetooth with my phone and says it has the latest upgrade. Once side comment, thought the bluetooth is nice, not very practical that it times out after 15min and you have to go to the thermostat to turn the bluetooth back on. I find I only used it once to calibrate temp/humidity and update the software.

    1. You may want to contact our app’s developer regarding this issue. You can contact them at 1 (425) 529-5775 or through email at [email protected]. As for the temperature issue in general, please give us a call at 270-366-0457 as soon as you can.

  27. I assume the wide range temp issues hasn’t been addressed yet? Just installed mine a couple days ago and mine does the same.

  28. Well folks the temp isn’t solved yet and no posted work around that I can see. However, as I person posted already you can test and test for a few to see how much of a difference in temp and setting there is. Then turn up your setting to adjust room temp. Mine appears to be off about 3 degrees i.e. I set temp to 80 and room gets to 77 on a separate thermometer and for the most part the remote reflects 77 as well or 78 depending on when it last sensed the temp. The wall unit will also say 77 or 78 so not that bad. Now the unit will also cool room down as low as 76 (even set to 80) which I am thinking is because it cycles on and off. Checking temp at unit air flow, it seems unit is always cooling on a low setting with fan auto set. I.e. it always runs compressor on low. Does not appear to rune just fan. this might be as designed may not. Long story for fix is turn up setting to match delta in your readings then tell everyone that if you want 75 degrees ensure you plus up the setting by the delta amount and prepare for times when room will fall 2 degrees below the desired 75. Unles ….. MrCool has an answer or other mitigation procedures or settings to address this.

    1. After every comment I’ve read, it’s clear they have no interest in dealing with this issue, so I too made the appropriate move in living with it as is. If you want it at 72, then set for 76. Easy peasy. But is doesn’t relieve this company of its responsibility to its customers in fixing a known issue that’s been happening for years, as they’ve done zero to address it.

  29. How do you Master reset the unit? Also is it normal for the 9000 to barely blow air out unless on turbo? On auto you can barely feel any air movement, I still love y MR. Cool !!!!! Also I read that I can run 2 9ks and the 18k but they wont operate at full capacity. Any thoughts on this???

    GEN 4 18k 9k

    Thanks so much!!


    1. To reset, turn the entire system off, then turn the system off at the breaker. Wait a few seconds, then turn the breaker then the system on again. The 9k should blow substantially when on. You may want to give us a call at 270-366-0457 for assistance regarding this issue.

  30. I am also having temperature control issues. I have used the internal temp sensor, the remote in Follow Me mode, I have ran in heat and in Auto modes. I have a Mini Stat on the way, but from what I’ve read, I don’t see that it will control any differently than the remote, just looks better.
    I have the set temp at 68°. The units continue to run and blow heat to maintain 74° and it’s too hot in the room. I have turned the set point down to 62°, but the unit still seems to maintain 74° in the room.
    Since Thanksgiving I have called and left a couple messages, I have emailed a couple times and I have chatted on FB messenger with a rep, but no solution and no Tech support help yet. Please contact me or send me a number where I can actually speak to a Technical Representative to help troubleshoot this issue.

  31. two things:
    1. I too am experiencing this whole temperature control problem. Last night, the living room unit, set to 70, was still not heating when the temperature in the room was 65. This is SO unacceptable.
    2. In an effort to see if I could resolve this, I bought a couple of ministats to contol a couple different units on my system and I can NOT figure out how to connect them to the wifi – only bluetooth, which is unacceptable.

    Can someone tell me how to connect the unit to the wifi?

    1. Right now, in a room, I have the remote set to 70 and in follow me mode. It thinks it is 67 and the stupid unit is not running because, it is reading the temperature from the unit which is around 72ish. If I turn it up to 73, it will turn on.

      The stupid follow me isn’t working correctly. It isn’t disabling/overiding the onboard unit temperature which is always much higher than the room

      FIX THIS. Had I known that this was going to be such a pain, I never would have invested so much time and effort into this product

      1. We apologize greatly for this. Please give us a call at 270-366-0457 as soon as possible so that we can assist you with this issue.

      2. David, I’m having the same problem. From what I gather, this is normal. Mr. Cool, correct me if I’m wrong but there is not an external thermostat in the remote, there is also not an external thermostat in the mini-stat. And, it’s not possible to hook up an external thermostat of any kind. I plan on buying a dumb thermostat to hang on the wall and i’ll just look at it and continuously adjust the Mr. Cool manually to try to maintain 72 degrees.

  32. Can Mr Cool please explain how the auto fan feature works on cool mode?
    Mine doesn’t work ( the way i think it should, logically).
    It “should” , raise and lower the fan speed to achieve the desired thermostat set temperature. Mine (both units) just sits on low in auto fan mode no matter what…..

    I’d also like to add, i would have paid $20 or whatever more for the remotes to have had bluetooth instead of ancient technology ir remote transmitters. This would have made the remotes actually “follow” you without having to have “line of site” and a limited reception distance. JS…..

  33. I’ve been having the same issue with my 4th gen 9k in my newborn’s nursery. Our baby monitor displays temperature and as you can imagine it’s quite concerning when I see it’s above 80 or below 65 in the space during the night. I have tried all the things stated above also to only find that most occasions result in over cooling or heating the room. As an HVAC engineer I attribute the issue to a couple things: 1) the indoor unit is oversized for the room 2) the controls likely don’t disable refrigerant from flowing through the indoor coils when set point is reached 3) the indoor units integral temperature sensor.
    Agreed it would be REALLY nice if there was an option for an external thermostat which could be used to control the unit more precisely but I’m not sure that is possible given the packaged controls. I do think 4th gen remotes do have an integral thermostat (Mr cool please comment – we are all confused how follow me mode works if it doesn’t).
    Regardless, I have come up with a hack that seems to work for my situation. Basically switch to fan mode once you get above heating set point or below cooling set point, which recirculates the air instead of recirculating and conditioning it. See comfy mode settings below for a scenario where we maintain temp between 71and 75 while heating. It would be sorta reversed for cooling. For 2 whole days we’ve actually stayed within the range and I’m gettin less worried about keeping my baby’s room warm (but not too warm) in the coming winter

    Temp range 71 – 75

    Temp below 71 power on
    Mode heat
    Temp 73
    Fan auto

    Temp above 75
    Mode fan

    Fan low

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