A DX HVAC system is a type of air conditioning system that uses direct expansion technology to cool and heat a space. It is a combination of an air conditioner and a furnace, and is the most common type of HVAC system used in residential and commercial buildings. DX stands for direct expansion, which refers to the process of cooling or heating a space by directly expanding refrigerant through a coil. This type of system is designed to provide efficient cooling and heating for a space, and is typically used in climates where both cooling and heating are needed. The DX HVAC system is an energy-efficient way to provide both cooling and heating to a space, and is a great option for both residential and commercial buildings.