We love our Alen air purifier we bought the Alen 75i because our daughter was just diagnosed with asthma between the pollen and pets it was really rough and she’s been staying sick so at this point we where going crazy trying to figure out how to help her . I have to say I’ve noticed a difference in our house air my daughter is feeling much better so that tells us this machine is working . We went to look at the filter and oh boy this thing is sucking up some dust, dirt and hair .. we absolutely love this machine and very much recommend.. we want to buy the filter for pets and try it but for now we have the pure sense filter