Did a lot of research, settled on this air purifier. Noticed a HUGE difference on the FIRST day. I've had mine for about a year, and really really like them. I had never owned an air purifier before and thought it might even be a scam to "clean" the air. I was wrong. Once I pulled out the filter and see the gray air it sucked in, I was hooked. I bought more than 1, because we have a ton of allergy sufferers in our house. Highly recommended.