I’ve got an older nest learning thermostat and am using the current integration. It works but sometimes the api times out and it’s obviously not local. I know there are other local thermostat options but the family likes the aesthetic and is comfortable with how to use it.
I’m wondering if the newer nest thermostat that supports matter is supported as a matter device and would be 100% local. I think It should work but If anyone can confirm that would be helpful.
I am guessing that the lack of responses means that no one really knows. If I get a chance to test this I will report back.
Interesting question – did you get an answer or managed to test this yourself?
I have not coughed up the cash to test this.
Fair enough 
According to this article it seems likely!
https://9to5google.com/2023/05/11/nest-thermostat-homekit-matter-set-up/
Don’t know, if the device still works after you cut the Internet connection though…
I really like the design, maybe I’ll give this a try in the future
Just got done replacing my Filtrete Radio Thermostat CT50 with local API (which worked but continuously had connection time outs with HA but worked pretty well. When they killed the RadioThermostat App, that is when I started using HA in home “production” environment .
I put in a Venstar Color Thermostat T7900. This device has a bult in secured API. I got it setup and connects very easily to HA once I figured our I has to setup the local API on the device.
Have not severed access to the internet yet but the local API it fast and very responsive in HA so far
How did this work when you cut the internet?
Can confirm: I have a new Google Nest Thermostat working over matter while disconnected from the internet. Only been testing for an hour or so, and will reconnect to the internet (thermostat provided gratis by the power company, so they want to see it online) but I’m pleased to see matter working for local control.
Here are the entities it enables:
* climate.nest_thermostat
* hvac_modes: off, heat, cool, heat_cool
* min_temp: 50
* max_temp: 90
* friendly_name: Nest Thermostat
* supported_features: 387
* current_temperature: 71
* temperature: 74
* target_temp_high: null
* target_temp_low: null
* sensor.nest_thermostat_temperature
* state_class: measurement
* unit_of_measurement: °F
* device_class: temperature
* switch.nest_thermostat
* device_class: outlet
Does not appear to allow fan control (still testing) but I can change the temperature and on/off/heat/cool. The matter linking process was a little convoluted, as I had to fiddle with both the Home Assistant Companion app and the Google Home app (can’t find the matter pairing code anywhere, so I’m guessing the Google Home app is hiding this) but at the end of the day I have local control!
I bought a Meross MTS300 and installed it yesterday, but I found that I’m missing the hvac_action attributes (cooling, heating, etc.) that tell me when the thermostat is running the HVAC equipment. I was using this to drive other automations.
I was considering buying a 4th gen Nest (I was running a 1st gen Nest). The entity list looks identical to what I’m getting with my Meross thermostat. I’m guessing they share some hardware / software.
Would you mind checking to see if “hvac_action” is present via the matter integration when the heat or AC is running with your 4th gen Nest?
- platform: template
sensors:
hvac_cooling:
value_template: "{{ is_state_attr('climate.central_hvac_thermostat', 'hvac_action', 'cooling') }}"
friendly_name: HVAC Cooling
- platform: template
sensors:
hvac_heating:
value_template: "{{ is_state_attr('climate.central_hvac_thermostat', 'hvac_action', 'heating') }}"
friendly_name: HVAC Heating
Unfortunately, it looks like “hvac_action” is not exposed via matter.
I talked to Meross support and they’re going to add it. I’m expecting a beta firmware in approximately 2 weeks
@virtualbitzz just added the MTS300 as well. Am trying to get local control of HVAC as Nest is retiring my old first gen device and I don’t want to spend a lot of money on the new one. LMK when the beta releases and, if you don’t mind, how to access it. I want automatons too!
Any word on whether we can control the Fan too? I like to do this according to CO2 buildup in bedroom at night.
also, how did you set up the MTS300? Did you have to add to Apple Home first? I have had a hell of a time getting it to pair to any Matter controller (I’d prefer HomeAssistant’s, but in the app workflow it defaults to an Apple Home addition, probably because I am on iOS). Right now it’s just running in Meross’ app and the app screen for Linked Services says:
This device failed to add to Matter system. It cannot be shared with Matter platforms like … To manage and control this device with Matter platforms, you need to reset it and re-add it to Meross app.
Frustrating.
I had Thread configured already via OTBR. That probably took care of some prerequisites like IPv6, mDNS, etc. I also had Matter configured with several devices on net already. I don’t use HomeKit
I added it to the Meross app first, then got a pairing code from the app, which I paired to HA Matter. You need the Meross app for initial config
Got it all set up in Apple Home and Home Assistant (and the Meross App as required to start due to the HVAC configuration).
Confirming that I now have the thermostat ip blocked (no access to internet) and Matter control from HA and Apple Home works fine. The Meross MTS300MA can be a local device! (It just requires cloud access for initial setup)
I also just sent the following feature request to Meross support, in line with what you asked for:
At some point, though I figure this is not Matter supported, it would be awesome if we could override the thermostats current temperature (e.g., to a temp sensor in a target area). Handling this now with clumsy automations, but would be fantastic to have this be native. The old Nest app allowed you to set the device to cool to a target temperature sensor, which I used.
Did they ever get back to you with an updated firmware?
Not yet, will follow up
I just purchased 5 of Nest 4th gens and made a simple integration - GitHub - darki73/hacs-nest-matters: Combines Google Nest and Matter thermostat entities into a unified Home Assistant climate control interface
Problem is, matter only exposes temperature setting and the reading, and thats it. This component aims to merge the Matter + Google Nest integrations, so you can have fast and unlimited temperature control (via Matter) and then for other features use the super limited (5 queries per minute / 100 per hour) Google Nest integration.
The combined entities will appear as a separate climate devices.
And then the temperature control + reading are provided by the Matter part, while the rest is routed through the Google Nest (you wont be changing modes very often, so i guess this is the best of 2 worlds)
I have a basic HVAC system that only allows to cool and control the fan mode (air recirculation while not cooling)
I got to the try the new beta firmware. They tried to implement it but there’s a bug somewhere, so it’s still not working. I actually got ahold of the product manager, I’ve been exchanging emails with him, they’re still looking at it. I’ll keep you guys posted.
It turns out the “bug” was on the HA side. I fumbled my way through a PR with a lot of help from some devs and got it working. It’s been merged, but not sure what release it will end up in. Basically needed to support values 5 and 6 for ThermostatRunningState, but should result in proper hvac_action reporting.
