We have a 12-year old German Shepherd & domestic quail as pets. We live in the desert & have LOTS of dust! Our main living area is all open, including the living room, dining room, family room & kitchen. I purchased the air400 Air Purifier to cover this entire area. I've been extremely pleased with how well it is keeping the dust down. It automatically works extra hard when I'm vacuuming & cleaning. My allergies have been worse this year but have improved since I set up the Air Purifier!