We love this Honeywell unit! We have 4 litter boxes in office for our 5 cats. We are ultra clean with the animals and the house but wanted to remove stale air in office. Office is about 11x11. This helps out tremendously with that issue. Not a replacement for lazy people who don't clean regularly. We run 24/7 and go tthe extended warranty. Oh, and as usual Overstock was the cheapest on the NET for this unit!!. I am a search hound for the cheapest price on the net.