Hi, I bought the large size air purifier about 4 months ago and liked it so much I bought a bundle of 3 mini air purifiers a couple of weeks ago. They are great. I feel so much better about the air in my home. I keep them running on the auto setting and it is fascinating to see how they work. The other night I was polishing my nails and the mini that was close to me kicked in. I never have even thought about what nail polish does to the air we breathe. The purifier picked up on the VOCs in the nail polish! My husband was grilling steaks which started to burn and the purifier setting near the patio door kicked in to clean the air. Things smelled better fast. I am super happy with the Sans air purifiers. The water purifier also works great. I also know Sans stands behind their warranty. Great company with great products!