Both air conditioners and coolers are effective, but the best choice often depends on the local climate and air quality. Air conditioners provide more consistent cooling and better humidity control, which is often preferred in very hot, humid environments to prevent heat rash. Coolers can be a cost-effective alternative in drier climates, but they require regular cleaning to ensure they don't circulate allergens or mold spores. Regardless of the cooling method, ensure the device is not blowing directly on the baby and keep the room well-ventilated to maintain air quality.