DX, or Direct Expansion, describes a refrigeration process where the air is cooled directly by the refrigerant circulating through the evaporator coil. Unlike "chilled water" systems used in large skyscrapers, a DX system like our Single-Zone models is simpler, more reliable, and more cost-effective for residential use. In a DX setup, the refrigerant expands and evaporates inside the indoor coil, absorbing heat from your room air in one direct step. This heat is then transported to the outdoor Condensing Unit to be released. This "closed-loop" technology is highly efficient and allows for the compact design seen in modern split systems. It also reduces the maintenance burden, as there are no large water pumps or cooling towers to manage. All OLMO Multi-Zone systems utilize advanced DX technology to provide rapid cooling and heating. It is the gold standard for modern, residential climate control efficiency.