During cold and flu season, I caught a cold and a friend loaned me her Whirlpool air purifier in hopes that I would get over the cold without catching it from myself again or infecting my family. It worked so well, I was over it in two days, and no one else got sick. I kept the purifier at my house for about 1 month afterwards, just to ward off any other potential colds, and during that month, I realized that I was actually feeling better than usual. I loved this purifier so much that I purchased my own, slightly different Whirlpool purifier. It works equally as well as the other, so I am assuming all Whirlpool purifiers work great. Since I bought my Whirlpool, my allergies have gotten better and the air in my house smells cleaner. The filter is simple to change, and the sound it makes is not loud like some other purifiers I have owned. In fact, it sounds like a fan would, just a low air flowing sound. I love this purifier since it reaches every room and works great, and as an added bonus it is an Energy Star appliance, which is always good news.