My son has asthma and severe allergies and we needed an affordable air purifier that REALLY works. After researching, PureZone met the bill and has exceeded our expectations. We purchased 4 of them for various rooms throughout our home. We have not had an issue with any of them. I love that I can set the purifier on a timer to run for 4 hours, 6 hours, or all day. I've recommended this product to several others!