Why the heck can't a generic thermostat control both a heater and an AC?

I have an HVAC unit that I control through Harmony. The unit has heating and cooling modes, but generic thermostat can only control a single switch. The documentation says you would need two thermostats if you want to control heating and cooling.

There are custom components for this. Or you can work around it natively by making a single switch that calls a script that chooses whether to turn on the heater or AC, but since you can’t change the thermostat’s ac_mode, your script has to use some inverted logic to force it to behave like a heater or an ac (whether hitting some temperature means it should turn on or off the device).

My ask would be to at least add a climate.set_ac_mode service. Ideally adding a second switch option for AC.

I’m with you. I’ve had to set up multiple climate integrations which have sent me crazy.

I leveraged some old projects and have a custom component to do just that: Climate: Dual Mode Generic Thermostat