Blow-through design refers to an HVAC configuration where the blower fan is positioned "upstream" of the heating or cooling coils, pushing air through them. This is the opposite of a "draw-through" design and is commonly found in certain Air Handlers and rooftop units. One major advantage of this design is that it creates a more uniform air distribution across the coil surface, which can improve heat exchange efficiency. In Mobile Home Air Conditioners, this configuration helps keep the motor cooler by having it handle unconditioned air rather than air that has already been chilled. However, because the air is under positive pressure, any leaks in the cabinet will push air out rather than sucking unfiltered air in. This design is often used in Commercial Packaged Units where higher static pressures are required to move air through long duct runs. Understanding the design of your unit helps in troubleshooting airflow issues and ensuring the filter is placed in the correct location.