This article applies to all ecobee thermostats except Smart, Smart SI, EMS and EMS SI.
AC Overcool Max can help reduce excessive humidity in your home even if you don't have a dehumidifier installed. While it is not a substitute for a dehumidifier, it helps to decrease the humidity level in your home by continuing to run your cooling beyond your comfort setting.
This threshold setting can be accessed and configured by going to:
MAIN MENU > SETTINGS > INSTALLATION SETTINGS > THRESHOLDS > AC OVERCOOL MAX
Next, on this threshold page specify how many degrees your A/C system should overcool the home.
Next you will want to set your desired humidity point. This can be accessed by going to:
MAIN MENU > SYSTEM > DEHUMIDIFY USING AC > ENABLE
You will want to choose your desired humidity level.
By enabling this threshold, your air conditioning system will overcool your home. It will stop once it reaches your overcool max setting or until the humidity set point is reached - whichever occurs first.
For example, if your AC Overcool Max is set to 2 degrees, and your desired set point is 72 degrees, then the AC will continue to run until it is 70 degrees if the humidity is above 60%. However, if the humidity level reaches 60% before 70 degrees, then it will shut off.
Note: the AC will not engage until the temperature rises above the comfort setting. The desired humidity level does not affect when the equipment engages, only the set point.
Since air conditioning naturally removes humidity from the air, running a longer cooling cycle will bring down the humidity level in your home.