Ultrasonic humidifiers are devices that use high-frequency sound vibrations to create a fine mist of water, which is then released into the air. This process helps to increase humidity levels in a room, making the environment more comfortable, especially in dry conditions. They are often quieter than other types of humidifiers, such as steam vaporizers or evaporative humidifiers. These humidifiers are typically energy-efficient and can be used with distilled or tap water. Some models come with additional features like built-in hygrometers to monitor humidity levels or essential oil trays for aromatherapy. Regular cleaning is essential to prevent the growth of bacteria and mold.