The Lennox X4912 HEPA-20 is the mid-sized model, capable of cleaning 180 CFM of air on standard residential or commercial heating and air conditioning systems.
The X4912 with 180 CFM Model provides adequate filtration for a tightly-constructed home up to 1500 square feet.

The Healthy Climate HEPA By-pass filtration units are designed for installation in forced air systems or can be used independently.
When connected to the return air duct, the HEPA unit diverts some of the return air into a three-stage filter.
Then the cleaned air is returned to the return air duct to be heated or cooled. Designed to capture 99.97% of particulates down to 0.3 micron that pass through it. Constant blower operation will achieve the best air cleaning results with continual flow of dirt laden air cleaned by the HEPA filter. The first set of filters is included with the unit! 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. Click Here for the Lennox HEPA Product Brochure Click Here for Detailed Lennox HEPA Installation Instructions & Homeowner Manual Click Here for Lennox HEPA Product Engineering Data Sheet

• Airflow: 180 CFM
• Height: 14 inches
• Width: 17.8 inches
• Depth: 14 inches
• Filter Type: True HEPA