The BreatheSmart is a simple to use, carefree, and highly efficient air cleaner. We purchased this model to place in our common living areas. It cleans the air very well and its automatic adjustment features enables it to respond to changing conditions as well as makes it quite energy efficient. Disregard complaints about the sound the unit makes. You will easily become accustomed to the background "white noise" feature of this cleaner. The BreatheSmart is a remarkable machine whose self-adjusting features should be incorporated into a model for smaller spaces.