Why is my heat pump not heating in winter?

Heat pumps extract heat from outside air. In very cold temperatures (below -5°C), they become less efficient and may rely on auxiliary electric resistance heat.

Check if the outdoor unit is iced over. Excessive ice buildup blocks airflow and prevents heat exchange. If the defrost cycle isn't clearing ice, call a technician.

Ensure your thermostat is set to 'Heat' mode, not 'Emergency Heat' unless necessary. Emergency heat uses only electric resistance heat, which is much more expensive.