Sealed bypass design-traps particles and prevents them from escaping;Optional carbon filtration-helps remove odors;Powerful, yet quiet performance-completely and quietly filters the air inside the home, several times a day;Easy integration-designed to work with Lennox heating and cooling systems for total home comfort;True HEPA system-means the entire system has been tested to meet industry standards for particle/bioaerosol filtration;Near perfect filtration-up to 99.97% efficient in removing particles and bioaerosols down to 0.3 micron;No ozone emissions-a known lung irritant