I was going to wait for a few weeks to write a review, but I've had this thing for all of 15 hours and I am astonished at what a difference it makes! I live in Salt Lake, where we get inversions of smog for much of the winter. The inversion we've got going on right now is particularly bad. Kids can't even go out for recess some days because the air quality is so dangerous. My husband has asthma and every person in my house is sick right now. My mom ordered this for us for Christmas in hopes of getting some breathing relief. I tell you what, I woke up this morning with clear sinuses for the first time in MONTHS. I couldn't "hear" my husband breathe and didn't wake up to his snoring either. It was the best night's sleep I've had in SO long. I doubted that I'd be able to tell the difference between the dirty air and the purified air and I was so wrong. I am absolutely thrilled and WIDE AWAKE this morning! I will definitely be purchasing more!