The API doesn't give any information on the state of the HVAC system, i.e. heating, cooling, fan. Will this be added in the future?
You can determine the cooling/heating mode using the "hvac_mode" property (https://developer.nest.com/documentation/api#hvac_mode), and "fan_timer_active" to check if the fan timer is running. You can also query the target properties, starting with "target_temperature_f" (https://developer.nest.com/documentation/api#target_temperature_f)
No, HVAC mode isn't the same as HVAC state. My system could be in cooling mode but not actively making a call for cooling. If you know the swing value you can guess based on the difference between set point and actual temp but that really isn't reliable.
Presumably this might be to prevent replication of existing Nest functionality?
来源：https://stackoverflow.com/questions/24396384/will-the-nest-api-support-reading-the-state-of-the-system