Possible to use Nest 3 thermostat with 3rd party sensors?

I’m considering getting a Nest (3, learning version) for home, and I want to integrate it with HA. I already have four (non-Nest) temperature sensors spread out over my home, so if I get a Nest, could I use something like node-red to say ‘after 9pm, turn on Cool on Nest if bedroom_temperature is greater than 20’? Or is the Nest API for HA read-only, not allowing for any control?

Yes it’s possible to set the nest temperature.
What you need is an automation that will change the temperature depending of your sensor.
Action to change the nest temperature:

service: climate.set_temperature
target:
  entity_id: climate.nest_device
data:
  temperature: 21

How might one read and write the set temperature in node-red? I installed the nest integration but I only see three entities; a Dining Room entity (my nest’s location), a sensor.dining_room_humidity and a sensor.dining_room_temperature. Ideally I’d have access to the current set temperature of the nest, as well as a way to change that.

Hi,

The temperature is an attribute of the climate.diningroom (your dining room entity)
You need to set the temperature with this attribute.

See below, it was set to 20.5°C

image

Is it possible to do the setting of the temperature in node-red?

Yes.

Call service node,

You’ll need your entity ID.

Then in the data field

put

{“temperature”:“22”}

You’ll want to set your own temperature though.

Then call that node in your flow.