Why is my heat pump frozen and how can I fix it?

Your heat pump may be frozen due to a buildup of ice on the outdoor unit, which can be caused by low refrigerant levels, dirty air filters, or blocked airflow. To fix it, you can try defrosting the unit by turning off the heat pump and running the fan to melt the ice. You should also check and replace any dirty air filters, clear any debris blocking airflow, and ensure proper refrigerant levels. If the issue persists, it's best to contact a professional HVAC technician for further assistance.