I bought 2 of the Pure Enrichment - Pure Zone 3 in 1 HEPA Air Purifier. I put them in 2 of the bedrooms. I was very impressed that you couldn't hear them at all, they are so quiet. That was a plus because I am a very light sleeper. I have mold allergies and after it rained last night, I did not wake up with a stuffy nose. It purifies the air in the room. Can tell right after the first use. Good product.