In your mobile home's air handler setup, it sounds like you have a configuration commonly used in HVAC systems where the evaporator coil (evap coil) is situated at the top of the unit and the blower and furnace are positioned below it. The insulated, hollow "tube" hanging down likely serves an important purpose in the overall airflow direction and system efficiency.
1. **Air Flow Direction**: In this configuration, the blower typically pulls air


