I bought the BreatheSmart 75i thinking it would just be another air purifier. My family and I have been using it for almost a month. At the beginning when the red light turned green I thought it was just propaganda. Now my wife and I can see the difference when we turned them off . In our living room we have a dog and a cat, I've never noticed the dander affecting my breathing, after using the 75i I'm able to breathe better. During the night, we have a second unit in our bedroom, I used to wake up with a dry mouth because my nostrils were always clogged and had to breathe through my mouth. Now, I wake up with a regular mouth, nostrils are no longer clogged. In short, I'm a believer in this product.