Lennox X6667 Filter

The Lennox X6667 is an OEM high-efficiency pleated air filter engineered for the Healthy Climate PureAir PCO-20C air purification system. This specialized 21x26x4 canister-style media is critical for maintaining the intended static pressure and airflow velocity required by Lennox air handlers. While historically rated at MERV 10, the newer X666701 specification often reflects an upgrade to MERV 11 efficiency, providing superior capture of microscopic contaminants including pollen, mold spores, and pet dander down to 0.3 microns. Built with a moisture-resistant beverage board frame and electrostatically charged synthetic fibers, this filter provides a high dust-holding capacity without causing excessive pressure drop across the evaporator coil. Professionals should note the actual dimensions are approximately 21-1/8" x 26" x 4", ensuring a gasket-tight seal within the PureAir system housing to prevent air bypass and protect downstream secondary heat exchangers.

Key Benefits:

• OEM Compatibility: Precision-fit for Lennox PCO-20C cabinets and replaces legacy part numbers including 75X67 and 100898-05.
• Enhanced Filtration: Synthetic MERV 11 media captures 85% of particles sized 3.0 to 10.0 microns, optimizing indoor air quality.
• Structural Integrity: The pleated design is supported by a 30-gauge galvanized metal grid to prevent media collapse under high-velocity airflow.
• System Protection: Reduces debris accumulation on blower motors and coils, maintaining peak HVAC system efficiency.

Common Questions:

What is the difference between Lennox X6667 and X666701?
They are functionally identical. The X666701 corresponds to the updated manufacturing catalog number, ensuring the same 21x26x4 fitment and filtration performance.

How often should this filter be replaced in a residential setting?
For standard HVAC maintenance, we recommend inspection every 6 months. In high-particulate environments or homes with pets, more frequent changes may be required to prevent increased static pressure.

Will a generic 21x26x4 filter work instead of the X6667?
Generic filters often vary in actual depth and frame rigidity. Using the Genuine Lennox X6667 ensures the filter integrates correctly with the PureAir PCO-20C's specific internal dimensions and airflow requirements.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.