This article applies to all ecobee thermostats except Smart, Smart SI, EMS and EMS SI.
Auto mode on your ecobee thermostat is great for maintaining a comfortable home temperature in milder climates or in-between heating and cooling seasons. While on this system mode, the ecobee will display two set points—one for heating and one for cooling. The cooling set point is blue while the heating set point is orange.
To enable this system mode, go to Main Menu > Settings > Installation Settings > Thresholds > Auto Heat/Cool and select Enable.
Once enabled, you should be able to activate Auto either by taping on the system icon above the thermostat temperature reading on the main screen or by going to Main Menu > System > HVAC
How it works
If the temperature goes above the blue cooling set point, the ecobee will turn on your cooling equipment to lower it down to the desired level. In the same way, the ecobee will turn on the heating equipment should the temperature drop below the heating set point.
The minimum allowable gap between the two set points is determined by the Heat/Cool Min Delta threshold. You can edit this by going to Main Menu > Settings > Installation Settings > Thresholds.