I have bad allergies and needed something to help with mold, cedar and two dogs that shed a lot. After doing some online research I ordered this unit and I placed it in my bedroom. I then turned it on high and turned on the UV light, closed the bedroom door and let it run for about an hour while I did a couple things. When I opened the door it was a very noticible difference as it knocked out the bad pet smell and the air was much cleaner. That evening when I went to sleep, I put the unit on medium and left the UV light on and I made it through the night without sneezing and my eyes didn't itch nearly as bad. For two weeks now, I'm feeling much better. I ordered another one for my son and put it in his bedroom and it's working great. Then I bought two more so now I have 4 units. I didn't know what to expect upfront when the first one arrived, but I can honestly say it has made a difference and I am sold. During the day, I turn off the unit in the bedrooms and close the door, and turn on the one that is now in my family room. I have found if you turn it on HIGH for an hour with the UV light on it knocks out the allergens. Then right before I go to sleep, I'll turn off the UV light and leave the unit on medium for the rest of the night and it works great. The real test will come this January when Cedar hits as it gets really bad where I live, but I have no doubt I will see a big difference. If you buy this, you should definitely feel a difference. The other thing I like is the unit is not loud which makes it easy to fall asleep. When turned on the UV light that's located inside the unit is visible and not very bright, but it is also accompanied by a blue light on the top of the unit which at night is pretty bright for me. Keep this in mind when you decide where to place the unit as it can also double as a small night light. However, if it's a problem, without turning off the power button, you can just turn off the UV light which is separate. It appears the UV light really does it's job and I haven't had to keep it on all the time, but for the first 3 days I did just so it could knock everything out in the air. I don't usually write a product summary, but I feel this one is worth it.