The NOMA 4.0 Liter (1.05 gal) Evaporative Humidifier seamlessly blends superior design with functionality and maintains humidity in indoor spaces during long dry seasons. Its large room capacity makes it ideal for spaces up to 380 sq. ft, and the top fill design allows for simple refilling. Use the humidistat to set your preferred humidity to 40%, 50% or 60%. Let it run continuously for 24 hours or use timed shut-off options to set humidifying time for 2, 4, or 8 hours. At 40 dB, this humidifier runs quieter than the library.