While a high-performing HVAC system with adequate air filters helps clean your home’s interior air, it is also a good idea to add an air purifier. Air filters trap dust and bigger particles prevalent in the air, preventing them from flowing throughout your home; this helps keep your HVAC system functioning smoothly, but it isn't enough to keep your interior air completely pure. An air purifier, on the other hand, is a device designed to do one thing: clean the air you breathe by removing such pollutants as bacteria, mold, mildew, pet dander and pollen.