Why You Really Need to Change Your Air Conditioner’s Filter

More important than which filter you buy is how you use it, Siegel says. Priority number one: replacing or cleaning it regularly. If you put it off for too long, mold and other contaminants can accumulate in your AC system and circulate throughout your home, potentially triggering allergies and other respiratory issues, says Anthony Gerber, a pulmonologist at National Jewish Health [and professor of medicine at CU School of Medicine].