Works magic – My son has bad asthma. This product has been the best thing, I can tell when its off in his room as he is coughing, Turn it back on in 5 mins he stops. Since owning this product his asthma is now under control. I couldnt live with out it. I would say to anyone that has asthma or breathing problems please go out and buy a winix ultimate 5. they can change the way you live