Found insulation had peeled off and was blocking airflow to the electric heat and cutting down air flow on heat pump significantly. Removed tested defrost and insured the back up heat activated in a call for defrost. Attempted to reattach insulation but was unable. Informed customer of my findings also informed customer that they should keep the system at a steady temp as it will take longer to make up the temp differential from night to morning and ultimately makes the system ineffeciant. Also noted that the temperature differential between thermostat and actual temp of the room is 10 degrees this is due to the location of the thermostat and may need to be insulated or moved to overcome.