Medify Air 2-Pack HVAC filter with a MERV rating 11 and HEPA material attracts and removes microscopic particles like dust smoke pet dander pollen and smog particles removing them from the air you breathe. The HEPA-Type filter protects your home removing 95% of airborne particles wihtout impacting the air flow of a furnace or HVAC. Homes with smokers or a wood-burning fireplace should pick MERV 12-13. MERV 14+ are generally for hospitals schools and environments with high air quality requirements. SUIT YOUR NEEDS: If you have pets or allergies MERV 11 is a great baseline. Homes with smokers or a wood-burning fireplace should pick MERV 12-13. MERV 14+ are generally for hospitals schools and environments with high air quality requirements. High-grade HEPA filtration (H13) that removes 99.9% of airborne particles down to 0.1 microns.