DIAGNOSIS: Your heat pump differentials are set too aggressively. The system is staging in aux heat before the heat pump has a chance to work.
FIX: Adjust the compressor to auxiliary heat delta.
- Go to MAIN MENU > SETTINGS > INSTALLATION SETTINGS > THRESHOLDS.
- Select CONFIGURE STAGING MANUALLY.
- Select COMP TO AUX DELTA.
- Increase the value. This sets how many degrees the indoor temperature can drop below the setpoint before aux heat engages.
IF THAT DIDN'T WORK: Your heat pump may be locking out due to cold outdoor temps. Check the minimum outdoor temperature setting. Go to INSTALLATION SETTINGS > THRESHOLDS > COMPRESSOR MIN OUTDOOR TEMP. If set to a fixed value, the heat pump won't run below that temp. Consider disabling this to let the ecobee maximize heat pump use.
HEADS UP: To prevent short cycling and improve efficiency, increase the HEAT DIFFERENTIAL TEMP in the same THRESHOLDS menu. This makes the system wait for a larger temperature drop before turning on.