We bought 2 of these purifiers when we found out we were having a baby, one for upstairs and one for downstairs. They have been awesome for keeping the air smelling fresh and clean. 2 years later, they started making a loud buzzing sound, within weeks of each other, that wouldn’t go away after cleaning and changing both filters. I called customer service and Rosa was happy to help in exchanging both defective units. I have been pleased with ALL Pure Enrichment products that we own (Purifiers, Humidifiers, Dehumidifiers and Cloud products for the Nursery). They sure do stand behind their quality and reasonably-priced product. Thank you so much!