I suffer from severe allergies 365 days a year. I placed my purifier in my bedroom and set it for 8 hrs when I go to sleep. I have been using it for about a month and have noticed a dramatic difference in my breathing in the morning. I don't wake up full of congestion or sneezing. I have noticed when I'm at my office my allergies tend to act up, so I will be ordering one for my office soon. I highly recommend this product for other allergy sufferers.