Your furnace air filter should be changed every three or four months during normal conditions. But what if you live near dirt roads or have air quality concerns caused by local industries, wildfires, or red tides, for example? Don’t breathe that junk! Our SwiftAir 8 is a pleated furnace air filter with a MERV 8 rating that can improve air quality by trapping dust (and dust mites), ash particles, pollen, mold, lint, and other similar-size pieces of unhealthy floating trash. By cleaning the air you breathe, you can protect your health and prevent typical household pollutants from irritating your lungs, throat, and eyes.