I got the Meross Smart Matter+Wi-Fi Thermostat MTS300 US running today.
In case anyone is curious about what gets exposed to Home Assistant, here it is!
The installation was some what haphazard. I think I was supposed to install with the Meross app. But I'm not sure if that actually was needed. I think I installed via scanning the Matter code in Home Assistant... and then later it appeared in the Meross app. 🤷
The Meross app exposes fan controls. Also child lock. You can also create a schedule in the Meross app. None of these features are visible in HA. (Also cannot control display brightness via HA. Sad.)
Side question: how do y'all create a schedule for your thermostats? I feel like I shouldn't use Meross' scheduling features and I should keep all the smarts in HA, right? I guess I should create Automations and trigger them based on time of day?
Update 12 Nov 2025
Meross released new firmware! I updated my (now 2) thermostats to firmware 9.1.14.1.2.2 and I have fan control now!!! 🥳
I run all the scheduling in the thermostat, because I lose automatic recovery and some aspects of Thresholding, and the rest of the family doesn’t use HA. However, I can’t set certain items (for example, how often the fan runs) in the thermostat’s schedule so I automate those portions with HA.
Matter has limitations, and may not include all the capabilities you want exposed.
For the scheduling it’s basic. Wake, sleep, work, weekends. I have some settings for my high rate time periods as well, and use Proximity for setting the away thermostat.
Meross’s own FAQ addresses why you need to use their app for setup - it’s so that you can tell it what kind of system you have. It’s fairly important.