An Air handler is the perfect breathing ground for mold, why? An Air handler removes humidity from the air leaving behind algae build up on coils and pans which allows mold to grow on the inside of the unit and duct work. Not only does this affect the air you breathe but also makes the unit work harder. We suggest having your system service/tune up at least 2x's a year. Save 20% in repairs when you sign up for a maintenance plan.