My daughter has a strong allergy to dust mites and strong spurts we need you up to 4 drugs give a good nights sleep. I have to admit I was skeptical whether the air purifier can make a difference here. After the good Reviews we got ourselves the Philips AC4012 / 10. WITHIN a week we were able to sell all medicines. Our daughter (7 years) can now no Medications quiet sleep through the night. We leave in the child room the air purifier 2-3 hours before going to bed and go to sleep mode until we go to bed. Then we turn it off. The air in the room is palpable pleasant and has a nice fresh, which can be hard to describe. I hope the success is sustainable. After 2 weeks, but I am very satisfied. A worthwhile purchase has reduced the use of medication with us. Technology suggests Pharma :-)