The Evaporator Coil is the indoor component of your HVAC system where the actual cooling of your home takes place. As liquid refrigerant enters the coil, it expands and absorbs heat from the air being pushed over it by the fan. This process turns the refrigerant into a gas, which is then sent back to the outdoor Condensing Unit to release that heat. In our Wall Mount R454B 12,000 BTU units, these coils are engineered with high-grade copper and aluminum fins for maximum thermal transfer. If the coil becomes dirty or frozen, the efficiency of your Single-Zone system will drop significantly. Modern OLMO coils are often treated with anti-corrosive coatings to prevent "pitting" and refrigerant leaks over time. Proper filtration is key to keeping these coils clean and ensuring your system meets its SEER2 rating. When you feel that crisp, cool air, you are feeling the direct result of a high-functioning evaporator coil. This component is essential for every Multi-Zone indoor head in your home.