In the Help Center, there is a post by Google on "Fan Compatibility with Nest Thermostats." The post says that "Variable speed fans are compatible with Nest thermostats, but the fans will only operate at a single speed."
But in another Help Section, there is a description of how to change the speed of the Fan from the Nest Thermostat.
How do I reconcile these two sections? Can the Nest device operate multiple speeds or not? If the HVAC unit I have has a variable speed fan, can I change the speed of the fan from the App?
Thank you for taking the time to let us know about your inquiry. I understand this can be confusing, but I definitely wanted to see how I could help.
The Nest Thermostat (2020) and Nest Thermostat E are only compatible with single-speed fans, whereas the Nest Learning Thermostat is designed to work with up to three-speed fans. But if your system has variable-speed fans, the use of this type of motor means that the HVAC can finely control the temperature in your home by operating the fan at the speed required rather than relying on pre-defined speeds. They will only function at one speed and you can't adjust the speed.
Please let us know if you have more questions in mind.
Can you contrast this answer with that for the Ecobee? The Ecobee maintains they support variable speed
There are two constructs here:
Thanks for getting back to us and sorry for the delay.
The Nest Thermostats does not support variable speed fans. We're always looking for ways to improve and we'll take it as feedback.
I also suggest that you send feedback by following this link. Let me know if you have other questions or concerns, otherwise I’ll be locking this thread after 24 hours.