TT-MAC-1422 High Efficiency Whole House Air Cleaner standard with MERV 11 and upgradeable to MERV 15. Air cleaner that attaches to any forced air heating or cooling system. Helps maintain high efficiency levels of your HVAC equipment. Protect your family and home from airborne particulates, allergens, dust, and dander. Cleans the air in your entire home every time your heating or cooling system is turned on. Easy filter cartridge replacement lasts up to 12 months.