An "indoor unit" refers to the component of a heating, ventilation, and air conditioning (HVAC) system that is located inside a building. Its primary function is to distribute conditioned air throughout the indoor space, ensuring comfort for occupants. The indoor unit typically includes a fan, evaporator coil, and air filter, which work together to cool or heat the air as needed. Indoor units can vary in design, including wall-mounted, ceiling-mounted, or portable types. They are often paired with an outdoor unit, which houses the compressor and condenser. Together, these units form a complete system that regulates indoor temperature and air quality efficiently.