Every MClimate device of type relay (Bobbie, Smart plug, Shelly 1, Shelly 1pm, Shelly em, etc) can act as a thermostat. If it is configured as such, it can use sensor data from another device that have temperature sensors (Bobbie, Melissa, Vicki, Mom, HT sensor, Shelly 1/1 pm, AQI Sensor and notifier, etc.) and use the sensor as reference to control the heating load e.g. space heater, water heater, etc.