The most likely cause is your heat pump's auxiliary heat threshold settings are too aggressive.
Here is the fix:
- Go to MAIN MENU > SETTINGS > INSTALLATION SETTINGS > THRESHOLDS.
- Select CONFIGURE STAGING MANUALLY.
- Adjust the COMP TO AUX DELTA setting. This is the number of degrees the indoor temperature can drop below the setpoint before auxiliary heat engages. Increase this value.
- Also check COMPRESSOR MIN OUTDOOR TEMP. If set to a specific temperature, the heat pump will not run below that outdoor temp, forcing aux heat. The default is Disabled.
- Increase the HEAT DIFFERENTIAL TEMP setting to reduce short cycling and improve efficiency.
If that didn't work, the issue may be your specific heat pump's performance. The default settings rely on system feedback; if your heat pump is slow to produce heat, manually increasing the COMP TO AUX DELTA further is required.
Heads up: Maximizing heat pump use saves energy. Auxiliary heat (often electric strips or gas) is your most expensive heating source.