The Hunter air purifier model 30057 is a great size for smaller rooms. It has two separate controls. One just to turn on the fan and it sucks in the air from the room that needs cleaned. The other control is for the ionizer which completely purifies the air. Using the fan without the ionizer still works to clear the air, so you don't always have to have both on. The purifer also comes with a HEPA filter that does need to be changed every six months. There is a dial on the top that tells you when you need to change the filter. I have several Hunter purifiers and they are all very good. This size, I keep in my bedroom and I have never had any problem with it. It is great for cleaning the air if you have allergies or if you burn some food and smoke fills the place. This takes care of it so your smoke alarm doesn't go off. You do need to make sure that you don't have anything shoved up against it so that it works the way it is meant to. It also works best if it is elevated off the floor. I recommend the Hunter air purifier.