i got an alert about 'high humidity in equipment' on my ecobee, what does that mean?

Diagnosis

The "High Humidity in Equipment" alert on the Ecobee Smart Thermostat Enhanced is triggered when the internal hygrometer detects a relative humidity (RH) level that exceeds the safety threshold defined in the device's firmware—typically above 60-70% for an extended period. Unlike a standard "High Humidity" reading on your home screen, this specific alert is a diagnostic warning indicating that the moisture levels are high enough to potentially cause condensation within the thermostat's circuitry or the wall cavity behind the mounting plate. This usually happens for one of three reasons: a localized "micro-climate" where the thermostat is installed (such as a wall shared with a master shower or near a laundry room), a failure in your HVAC system's dehumidification cycle (such as a stuck relay or an oversized AC unit that short-cycles), or an actual leak in the refrigerant lines or condensate drain pan located near the air handler. To confirm, check the "Home" screen humidity reading; if it is consistently above 65% while the AC is running, your system is failing to remove moisture from the air. If the home reading is normal but the alert persists, you have a localized moisture pocket behind the device.

How to Fix It

To resolve this alert and protect your equipment, follow these steps to calibrate the environment and verify system performance:

1. Verify Current RH Levels: Navigate to the Main Menu > Settings > Installation Settings > Thresholds. Check the humidity settings to see if the alert threshold has been manually lowered. Ensure the current reading matches a standalone hygrometer placed next to the thermostat to rule out a sensor calibration error.
2. Clear the Alert: Once you have verified the air is dry, go to the "Alerts" tab on the device screen and dismiss the notification. If it reappears immediately, the sensor is still detecting moisture.
3. Optimize AC Run Times: If your humidity is high, your AC may be cycling off too quickly. Go to Main Menu > Settings > Installation Settings > Equipment Settings. Ensure "AC Fan" is set to "On" or "Circulate" rather than "Auto" for a few hours to help move damp air across the cooling coils.
4. Inspect the Wall Cavity: Gently pull the thermostat off the backplate. Use a flashlight to inspect the hole where the wires enter the wall. If you see damp insulation or feel a breeze of moist air coming from the wall, use a small piece of plumbers' putty or foam sealant to plug the hole. This prevents "wall-drafts" from triggering the sensor.
5. Check the Condensate Line: Go to your indoor HVAC unit and ensure the PVC condensate drain line is not clogged. A backed-up drain pan increases the humidity of the air being pushed through the ducts, which the Ecobee will detect.

If That Didn't Work

• Install a Dedicated Dehumidifier: If your HVAC system is oversized (too many BTUs for the square footage), it will cool the house quickly but leave the air damp. Installing a standalone dehumidifier in the basement or the area nearest the thermostat will lower the RH below the alert threshold.
• Adjust the "AC Overcool Max" Setting: In the Installation Settings, look for the "AC Overcool Max" option. Increasing this allows the AC to continue running a few degrees past the target temperature specifically to remove humidity, which can clear the "High Humidity" alert.
• Replace the Backplate: If the device was exposed to a leak or high moisture for a long period, the pins on the backplate may have developed micro-corrosion. Clean the gold contact points with 90% isopropyl alcohol and a cotton swab.
• Recalibrate the Sensor: If the thermostat consistently reads 10-15% higher than a handheld sensor, contact Ecobee support to request a remote sensor offset calibration for your specific serial number.

Heads Up

• Avoid Wall-Drafts: Always seal the wire hole behind your thermostat. Unsealed holes allow attic or crawlspace air to hit the sensor, leading to false humidity alerts.
• Check Filter Frequency: A clogged air filter reduces airflow over the evaporator coil, which significantly impairs the system's ability to dehumidify the air.
• Avoid Humidifiers Nearby: Never place a portable humidifier within 10 feet of the Ecobee Enhanced, as the concentrated steam will trigger the equipment alert and potentially damage the internal board.
• Monitor Dew Point: If you live in a coastal area, remember that high outdoor humidity can seep through poorly insulated walls, triggering this alert even if your AC is working perfectly.