Lennox X4138 Healthy Climate HEPA-40/60 Carbon Pre-Filter Three-Stage Filtration Process: – Stage 1: Pre-filter – an inexpensive pre-filter to remove larger particulates from the air. This is important to prolong the life of the HEPA filter. Rated MERV 6. Estimate life – 12 months. – Stage 2: HEPA – removes 99.97% of particulates down to 0.3 micron. Estimate life 2-5 years. – Stage 3: Carbon – 1/2 in. (13 mm) thick carbon filter for removing chemicals and odors from the air. Replace filter when it no longer seems to capture odors, or once every 3 months. Optional carbon canister can be used in place of the carbon filter. Estimated life of the carbon canister is 6 months. Features: – 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 – Sealed, Bypass Design. Contains particles and prevents them from escaping – Optional Carbon Canister. Helps trap and remove odors – Powerful, Yet Quiet Performance. Completely and quietly filters the air inside your home, several times a day – Easy Integration. Designed to work with any heating and cooling system for total home comfort – Warranty: 5-year limited warranty on covered components Make sure this fits by entering your model number. 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 Sealed, Bypass Design. Contains particles and prevents them from escaping; Optional Carbon Canister. Helps trap and remove odors Powerful, Yet Quiet Performance. Completely and quietly filters the air inside your home, several times a day Easy Integration. Designed to work with any heating and cooling system for total home comfort Warranty: 5-year limited warranty on covered components