Standard Features - True HEPA systemmeans the entire system has been tested to meet industry standards for particle/bioaerosol filtration. - Near-perfect filtrationup to 99.97% efficient in removing particles and bioaerosols down to 0.3 micron*. - Sealed bypass designtraps particles and prevents them from escaping. - Optional carbon filtrationhelps remove odors. - Powerful, yet quiet performancecompletely and quietly filters the air inside your home, several times a day. - Easy integrationdesigned to work with Lennox heating and cooling systems for total home comfort. - No ozone emissions a known lung irritant**. - 5-Year Limited Warranty on covered components.