AC Presence Detection & Smarter Standby Below Minimum Operating Temperature

[Luke2105-Loft59]

I've now owned a duo split AC unit in my small attic apartment for about a month. Using an ESP chip, I've integrated it natively into HA via MQTT, meaning I don't use the remote, the manufacturer's app, or their cloud system at all.

I control the unit exclusively through RoomMind, version 1.75, which works quite well. However, over this time I've noticed two things where RoomMind could potentially be improved further — both are ultimately tied to the same setting: the minimum operating temperature.

1. Behavior on absence

While my radiator thermostats reacted excellently to my absence this spring and switched into ECO mode, the AC unit ignores this completely and stubbornly stays at the setpoint temperature defined in the schedule.

How do I tell RoomMind not to use the AC today (absence detection doesn't work as described above)? Of course I could manually switch off climate control for the room, but that's not really what I want. Blind control and, if needed, heating via the oil furnace (spring, fall) should remain possible — it's just the AC unit that shouldn't run.

Currently I solve this via the settings and the minimum outdoor temperature. However, this setting has to be changed manually and can't be controlled via an automation.

Suggested solution: Ideally, RoomMind wouldn't rely on external automations for this and would work as autonomously as possible. Absence detection already works great with the radiator thermostats without me having to set up anything extra — RoomMind apparently derives absence there on its own. It would be great if the AC were handled the same way, but based on absence for the whole apartment rather than just the individual room. On absence, the AC should automatically switch to a standby/idle state, just like it's already solved for the TRVs via ECO mode — without any extra helper or external automation. Blind control and heating via the oil furnace should remain unaffected — this is purely about the AC unit.

2. No standby behavior below the minimum operating temperature

I obviously use the compressor protection feature for the unit, so that once the indoor temperature is reached, the unit keeps running by slightly raising the setpoint, avoiding short-cycling.

However, if the outdoor temperature drops below the configured minimum operating temperature mentioned above, the unit doesn't switch to standby — it stays in cooling mode with compressor protection active, meaning I have to intervene manually in the evening. This also can't be solved via an automation, since automations can't access the minimum operating temperature value — it's stored exclusively within the RoomMind integration's own directory.

Suggested solution: Here too, I'd prefer an automatic, self-sufficient solution from RoomMind. Instead of rigidly staying in cooling mode with compressor protection every time the minimum operating temperature is briefly undercut, I'd like a bit more intelligent logic that distinguishes between two cases:

1. Relative to sunset: RoomMind already uses sunset as a reference point for blind control. The same reference point could be used here — once sunset is approaching or has passed, it's reasonable to assume the outdoor temperature won't rise above the minimum again, so the unit could switch directly to standby.
2. Duration-based (configurable): If the outdoor temperature has already been continuously below the minimum for a configurable period of time, that points more toward an actual weather change than a brief fluctuation — in that case too, the unit should switch to standby. Ideally this duration should be configurable, since it likely varies by region/season.

Only for a short, temporary dip below the threshold (e.g. due to a passing cloud or a brief daytime weather shift) should the unit remain in cooling mode with compressor protection, to avoid unnecessary cycling or constant switching.

I did a quick search through existing issues/discussions first — #5 touches on turning off climate control when nobody's home, but more generally and not AC-specific or apartment-wide; #274 discusses per-room outdoor temperature thresholds, but for a different problem (global vs. per-room configuration) than the missing standby behavior described here. Neither seems to fully cover what's described above, but linking them here in case they're useful context.

Those are my thoughts on this. Looking forward to comments, further ideas from the community, and hoping snazzybean (cheers!) picks up a few of these ideas.