It works, I have been able to cut back drastically on allergy medicine, saved now for only the worst day. My husband, after being in the room for a couple hours, stops snoring, very beneficial for us both. I can leave it on at night and I am very noise sensitive. This is the first piece of equipment I have ever been able to do that with. Easy to clean prefilter, not like the canister types that you have to take apart. My dogs tend to end up sleeping in the air streams from the machine. We are all LOVING it. I would highly recommend this machine. I am going to get another for the front room, just saving up for it. It is expensive but worth it.