The 5500, our most powerful and quietest purifier with an updated, patented filter design. It is the pure air solution for extra large spaces, high ceilings and open concepts. The AirDoctor 3000 is the perfect purifier for large rooms in your home, including master bedrooms, living rooms, kitchens. Pair it with the AirDoctor 2000, our small and mighty defender that provides powerful purification for small rooms, medium/small bedrooms, nurseries, home offices and more.