CSRE National Practice Test

In a split-system HVAC setup, cooling happens when indoor air is drawn over an evaporator coil that contains refrigerant. The coil absorbs heat from the room air, and a blower pushes that cooled air through the ducts into the living spaces. The refrigerant then travels to the outdoor condenser to dump the absorbed heat outside. That indoor coil belongs in the indoor air-handling unit, usually positioned above the furnace, so it sits directly in the path of the house’s airflow and can drain condensate properly into the building’s drain line. The outdoor condenser is a separate unit outdoors where heat rejection occurs. Choosing indoors above the furnace keeps the system integrated with the home’s heating/airflow setup and simplifies drainage and maintenance. Placing the coil outdoors, in an attic, or on a roof would disconnect it from the indoor air stream and complicate drainage and service.