Ductless AC systems, also known as mini-split systems, are generally more energy-efficient than traditional central air conditioning systems that use ductwork. This is because ductless AC systems can be installed directly in the rooms they serve, eliminating the energy losses associated with ductwork. Additionally, ductless AC systems allow for zoned cooling, allowing you to cool only the rooms that need it, which can further reduce energy costs. Overall, ductless AC systems can be a more cost-effective option for cooling homes, especially in areas with hot and humid climates.