A lot of consumer-grade ACs use IR-based remotes which can easily be connected into whatever automation solution you have with something like a Broadlink bridge.
Yes, but only downside of that is beep sounds and stateless, while Echonet Lite can provide you all internal properties like outdoor temp and etc and also current settings.
You can't query those for the current room temp, current settings etc. So then if you mix the OEM app & your home automation app, things get messed up. IR bridges are a hack in home automation, when buying new stuff avoid them.
Just my personal opinion, but the thermometer on an A/C unit is kind of worthless unless you sit within a foot of the unit. I prefer being able to read a sensor on the opposite side of the room, or even several sensors throughout the house, rather than one on the A/C unit. I don't use any OEM app at all, just my own. The OEM ones never do exactly what I want, so I have to hack something additional onto their features anyways. Home automation systems are really personal anyways though. I'm sure anyone here who's implemented their own has their own unique opinions about what's best ;)
Now premium A/C unit in Japan like from Mitsubishi Electric features high precision temp sensor to detect room temperature. Even middle model has good sensor rather than simple temp sensor.
