I'm not aware of the details of the thermostat you are looking at, but the biggest benefit for a multi-split ductless owner is to give the unit a remote temperature sensing location. I have a DIY system using HomeAssistant, but it does what many of the other thermostats do, which is give the actual in-room temperature to the indoor unit.
In my case (2 head and 3 head Mitsubishi Hyperheats), the warm air would collect by the ceiling and cause the indoor units to short cycle. After moving the temperature sense location out to the middle of the room, the units now correctly come up to minimum power and just stay there, sometimes all day with very little variation.
Air circulation or fans can help too, but that is the main benefit of a smart thermostat designed for heatpumps - more accurate temp sensing, rather than scheduling or "nest-like" features.
In my case, I already use the application Home Assistant to collect data from my house and automate various things. In this case I already had little zigbee temperature sensors scattered through the house. I then use a little open source code on an ESP32 microcontroller that plugs into the indoor units in the same place that Mitsubishi controllers plug in. Home Assistant then takes the temperature value from the nearest Zigbee sensor and sends it to the indoor unit as the current remote temperature, which overrides the internal temperature sensor. [https://github.com/geoffdavis/esphome-mitsubishiheatpump](https://github.com/geoffdavis/esphome-mitsubishiheatpump)
In my case, this means 5 indoor units and 5 temp sensing points, one for each room. Of course, this is on two levels of an old house and the rooms have wildly different loads. It is more complex than I would recommend doing from scratch, but in my case it was relatively easy since I already had most of this system setup and running for other reasons.
In simpler cases you might put in Mitsubishi's thermostat and put the measurement location in a common point like a hallway that all the rooms connect to, and measure from there. Or one for each level, for instance.
Glad to hear this - planning to use the same esphome setup soon. I hadn't heard/seen someone use the zigbee temp sensors as part of it... but I actually ordered those too.
Nice.
The setup works quite well with the set\_remote\_temperature function. You'll want to make sure that your HomeAssistant automation that updates the temperature from your sensors (don't have to be zigbee, just whatever temperature sensor sources you have) resets the ESPhome device to use the internal temperature if the external sensor is unavailable.
So does the smart thermostat detect just the overall temp of the house and all the minis run to that one setting?
Or does the one thermostat have the ability to detect what all of the individual units are feeling and adjust each wall unit according to their individual reading in the smart thermostat?
Hope this makes sense
In my case, I already use the application Home Assistant to collect data from my house and automate various things. In this case I already had little zigbee temperature sensors scattered through the house. I then use a little open source code on an ESP32 microcontroller that plugs into the indoor units in the same place that Mitsubishi controllers plug in. Home Assistant then takes the temperature value from the nearest Zigbee sensor and sends it to the indoor unit as the current remote temperature, which overrides the internal temperature sensor. [https://github.com/geoffdavis/esphome-mitsubishiheatpump](https://github.com/geoffdavis/esphome-mitsubishiheatpump)
In my case, this means 5 indoor units and 5 temp sensing points, one for each room. Of course, this is on two levels of an old house and the rooms have wildly different loads. It is more complex than I would recommend doing from scratch, but in my case it was relatively easy since I already had most of this system setup and running for other reasons.
In simpler cases you might put in Mitsubishi's thermostat and put the measurement location in a common point like a hallway that all the rooms connect to, and measure from there. Or one for each level, for instance.
If I wanted to throw money at this to get the same function, does the Mitsubishi MHK2 do the same thing? (Be a remote temperature sensing location that reports back to the indoor unit?)
I believe it does, but only for a single indoor unit. IE, an MHK2 is a single wall unit and a single wireless interface for an indoor unit, and they are paired together. If you wanted to integrate multiple indoor units to a single remote sensing location then I think you need to move up to the PAR controls, which is where I get foggy on what works with what.
[https://www.mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.com/enter.mehvac.com/DAMRoot/Original/10006\\M\_M-Series\_Compatibility.pdf](https://www.mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.com/enter.mehvac.com/DAMRoot/Original/10006\M_M-Series_Compatibility.pdf)
Attach "smart" to anything and people will flock to it. If it doesn't have a constant internet connection it's considered old tech. I'll bet my dumb PAR-40MAAU far outlasts any Ecobee or Nest out there.
Edit: As u/phidauex has mentioned, one benefit is having remote sensing capability. When I had my furnace that was important as there were many hot and cold spots throughout my house. Now my circulation fan runs basically 24/7 (except for the defrost cycle) so now the temperature around my house is much more consistent. Measuring in a single location is practical, at least with my ducted Mitsubishi.
Edit2: Your family's comfort should be the primary concern. If your family prefers cold temperatures while sleeping and a toasty warm house during the day, by all means set a schedule and forget it. But understand that heat pumps have limitations and won't be able to provide the instant heat you get with traditional furnaces.
>But understand that heat pumps have limitations and won't be able to provide the instant heat you get with traditional furnaces
An argument against fiddling. Efficiency Maine argues this in opposition to setbacks and cut-offs.
People have different preferences on how to run things. I don't like the "set it and forget it" view....I don't want to heat my house if I am not there, that's pointless and expensive, IMHO. Yeah, it takes a while for a heat pump to heat up and I am fine with that (or...see #2).
But some reasons for smart thermostats:
1) Ability to program in schedules.
2) Ability to control remotely...if you are on your way home, you can start it heating.
3) Can participate in demand-response programs.
4) Have it controlled by temp sensors in different rooms.
I agree with all but the main assertion. Set it and forget it is (usually) the best option for comfort and efficiency.
It gets nuanced real quick tho. Example:
Away for 6 hours: 1 -2 degree set back is better (probably)
Away for 24 hours: 2-4 degrees (most likely)
Away for a week: crank that temp down and ramp it up slowly…. Unless your moisture and humidity are a concern.
While I hate rules of thumb. Mine are:
Set it and forget
But be comfortable
Because. Comfort and control.
Set back to sleep a bit. Make sure they are on. Vacation mode for extended time away. Etc.
I strongly rec a set and forget but I also turn my down at night to sleep a few degrees. (I get up first and don’t mind the cold so I ramp up temp manually) but a intelligent stat could do that for me.
My rule of thumb is 3 degree adjustments on a daily timescale.
I'm not aware of the details of the thermostat you are looking at, but the biggest benefit for a multi-split ductless owner is to give the unit a remote temperature sensing location. I have a DIY system using HomeAssistant, but it does what many of the other thermostats do, which is give the actual in-room temperature to the indoor unit. In my case (2 head and 3 head Mitsubishi Hyperheats), the warm air would collect by the ceiling and cause the indoor units to short cycle. After moving the temperature sense location out to the middle of the room, the units now correctly come up to minimum power and just stay there, sometimes all day with very little variation. Air circulation or fans can help too, but that is the main benefit of a smart thermostat designed for heatpumps - more accurate temp sensing, rather than scheduling or "nest-like" features.
Can you elaborate about how you moved the temperature sense location?
In my case, I already use the application Home Assistant to collect data from my house and automate various things. In this case I already had little zigbee temperature sensors scattered through the house. I then use a little open source code on an ESP32 microcontroller that plugs into the indoor units in the same place that Mitsubishi controllers plug in. Home Assistant then takes the temperature value from the nearest Zigbee sensor and sends it to the indoor unit as the current remote temperature, which overrides the internal temperature sensor. [https://github.com/geoffdavis/esphome-mitsubishiheatpump](https://github.com/geoffdavis/esphome-mitsubishiheatpump) In my case, this means 5 indoor units and 5 temp sensing points, one for each room. Of course, this is on two levels of an old house and the rooms have wildly different loads. It is more complex than I would recommend doing from scratch, but in my case it was relatively easy since I already had most of this system setup and running for other reasons. In simpler cases you might put in Mitsubishi's thermostat and put the measurement location in a common point like a hallway that all the rooms connect to, and measure from there. Or one for each level, for instance.
Glad to hear this - planning to use the same esphome setup soon. I hadn't heard/seen someone use the zigbee temp sensors as part of it... but I actually ordered those too. Nice.
The setup works quite well with the set\_remote\_temperature function. You'll want to make sure that your HomeAssistant automation that updates the temperature from your sensors (don't have to be zigbee, just whatever temperature sensor sources you have) resets the ESPhome device to use the internal temperature if the external sensor is unavailable.
Perfect. Thank you. If I hit a roadblock may I shoot you a message? Won't be until after the holidays/new year. This time of year kicks my posterior.
Sure, I'm no expert but I'd be happy to share what has worked for me if you have any issues.
So does the smart thermostat detect just the overall temp of the house and all the minis run to that one setting? Or does the one thermostat have the ability to detect what all of the individual units are feeling and adjust each wall unit according to their individual reading in the smart thermostat? Hope this makes sense
In my case, I already use the application Home Assistant to collect data from my house and automate various things. In this case I already had little zigbee temperature sensors scattered through the house. I then use a little open source code on an ESP32 microcontroller that plugs into the indoor units in the same place that Mitsubishi controllers plug in. Home Assistant then takes the temperature value from the nearest Zigbee sensor and sends it to the indoor unit as the current remote temperature, which overrides the internal temperature sensor. [https://github.com/geoffdavis/esphome-mitsubishiheatpump](https://github.com/geoffdavis/esphome-mitsubishiheatpump) In my case, this means 5 indoor units and 5 temp sensing points, one for each room. Of course, this is on two levels of an old house and the rooms have wildly different loads. It is more complex than I would recommend doing from scratch, but in my case it was relatively easy since I already had most of this system setup and running for other reasons. In simpler cases you might put in Mitsubishi's thermostat and put the measurement location in a common point like a hallway that all the rooms connect to, and measure from there. Or one for each level, for instance.
If I wanted to throw money at this to get the same function, does the Mitsubishi MHK2 do the same thing? (Be a remote temperature sensing location that reports back to the indoor unit?)
I believe it does, but only for a single indoor unit. IE, an MHK2 is a single wall unit and a single wireless interface for an indoor unit, and they are paired together. If you wanted to integrate multiple indoor units to a single remote sensing location then I think you need to move up to the PAR controls, which is where I get foggy on what works with what. [https://www.mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.com/enter.mehvac.com/DAMRoot/Original/10006\\M\_M-Series\_Compatibility.pdf](https://www.mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.com/enter.mehvac.com/DAMRoot/Original/10006\M_M-Series_Compatibility.pdf)
Attach "smart" to anything and people will flock to it. If it doesn't have a constant internet connection it's considered old tech. I'll bet my dumb PAR-40MAAU far outlasts any Ecobee or Nest out there. Edit: As u/phidauex has mentioned, one benefit is having remote sensing capability. When I had my furnace that was important as there were many hot and cold spots throughout my house. Now my circulation fan runs basically 24/7 (except for the defrost cycle) so now the temperature around my house is much more consistent. Measuring in a single location is practical, at least with my ducted Mitsubishi. Edit2: Your family's comfort should be the primary concern. If your family prefers cold temperatures while sleeping and a toasty warm house during the day, by all means set a schedule and forget it. But understand that heat pumps have limitations and won't be able to provide the instant heat you get with traditional furnaces.
>But understand that heat pumps have limitations and won't be able to provide the instant heat you get with traditional furnaces An argument against fiddling. Efficiency Maine argues this in opposition to setbacks and cut-offs.
People have different preferences on how to run things. I don't like the "set it and forget it" view....I don't want to heat my house if I am not there, that's pointless and expensive, IMHO. Yeah, it takes a while for a heat pump to heat up and I am fine with that (or...see #2). But some reasons for smart thermostats: 1) Ability to program in schedules. 2) Ability to control remotely...if you are on your way home, you can start it heating. 3) Can participate in demand-response programs. 4) Have it controlled by temp sensors in different rooms.
I agree with all but the main assertion. Set it and forget it is (usually) the best option for comfort and efficiency. It gets nuanced real quick tho. Example: Away for 6 hours: 1 -2 degree set back is better (probably) Away for 24 hours: 2-4 degrees (most likely) Away for a week: crank that temp down and ramp it up slowly…. Unless your moisture and humidity are a concern. While I hate rules of thumb. Mine are: Set it and forget But be comfortable
What are the genius add-one? Is it just EcoBee? Or something that works with the existing thermostat?
Because. Comfort and control. Set back to sleep a bit. Make sure they are on. Vacation mode for extended time away. Etc. I strongly rec a set and forget but I also turn my down at night to sleep a few degrees. (I get up first and don’t mind the cold so I ramp up temp manually) but a intelligent stat could do that for me. My rule of thumb is 3 degree adjustments on a daily timescale.