For ecobee Smart Thermostats:

Temperature and Mode:
"Ok Google, what's the current temperature in the <thermostat name>?"
"Hey Google, what's the <thermostat name> set to?"
"Ok Google, what's the temperature of my thermostat?"

Adjust Temperature:
"Ok Google, set the temperature in the <thermostat name> to <temperature>."
"Ok Google, set the temperature to <temperature>."

Increase/Decrease Temperature:
"Hey Google, increase the temperature in the <thermostat name>
"Hey Google, decrease the temperature in the <thermostat name>."
"Hey Google, increase the temperature in the <thermostat name> by <number degrees>."
"Hey Google, decrease the temperature in the <thermostat name> by <number degrees>."

Resume Schedule:
"Hey Google, turn off the <thermostat name> hold."
"Ok Google, turn on the <thermostat name> schedule."

Fan Control:
"Ok Google, turn the <thermostat name> fan on."
Note: If this returns an error, try "Ok Google, turn the <thermostat name> blower on."

System Mode:
"Ok Google, set the <thermostat name> to heat."
"Ok Google, set the<thermostat name> to cool."
"Ok Google, set the <thermostat name> to heat cool."
"Ok Google, set the <thermostat name> to off mode."

Equipment Status:
"Ok Google, is the <thermostat name> <equipment type> <on off>?"

For Switch+
Turn On or Off:
"Ok Google, turn on the <switch name>."
"Ok Google, turn on the <switch name> switch."
"Hey Google, turn off the <switch name."
"Ok Google, turn off all switches."

Check Status:
"Ok Google, is the <switch name> on/off?"
"Hey Google, are my switches off?"


See

https://support.ecobee.com/s/articles/What-commands-can-I-use-with-the-Google-Assistant