Have only had the unit for a little more than a week but seems to work as advertised. Appears to be well constructed and aesthetically pleasing. Very quiet on first 2 of 4 overall fan speeds and not terribly noisy on speed 3.
It works great. Have upstairs den where the cat likes to reside. The purifier takes care of the odor from the litter box and wet food. I am ordering the larger one for downstairs when they become available.
I received my 45i about 3 weeks ago and it works great!! It is quite, fits into with my decor and it filters out all the dander and dust with all my dogs! I would highly recommend it!
It's effective and quiet. Effective means that I no longer have a cough or congested nose at night. Quiet means a sleep comfortable with it on. Besides being quiet, the noise is not a constant fan; there's a variation, sounding like a light breeze through the tress. I've tried two other brands. I will buy another Alen 45i for the second bedroom.