Your air conditioning unit helps keep your interior comfortable by producing cool air. This air should also be fresh-smelling. If it, instead, releases a musty odor, it is usually the sign of a malfunction or a maintenance issue that could lead to one in the future. The following outlines some of these potential causes.

Why Does Your AC Smell Musty?

1. Clogged Filters

When your unit’s vents or filters are damp, they create conditions that allow mold to grow. Spores can then travel through your duct system, moving around the house. This fungus can cause sneezing, running noses, or respiratory distress—especially in those with preexisting breathing conditions. It also generates an unpleasant smell. Central heating and air experts recommend replacing your filters regularly and arranging for professional duct cleaning to remove the odor.

2. Frozen Evaporator Coils

An air conditioning unit successfully cools your home by drawing warm, humid air over evaporator coils filled with heat-absorbing liquid refrigerant. This process can cause the water in the air to condense. As such, ACs usually have a dehumidifying effect.

While this water is supposed to flow through a drain line into a drip pan, a clogged drain line can cause it to linger on the evaporator coil, where it can grow fungus. Restricted airflow from clogged filters can also stop it from getting new supplies of warm air, leading to the evaporator coils freezing. This could ultimately require unit replacement.

Therefore, to avoid these problems, replace the air filters regularly. Avoid running your AC if it is lower than 62 degrees Fahrenheit.

3. Overflowing Drip Pan

If the drip pan meant to collect the water from your evaporator coils becomes obstructed with debris, it’ll quickly fill up and start to overflow. Unless these drips are cleaned up, mold and mildew will grow in the area and create a musty smell. Check to ensure the pan is draining properly, and clean any water in the area immediately to counteract the issue.

4. Too-Large AC

Having a large system might seem beneficial, but it can cause the system to cycle cold air through the home so fast that it never has a chance to become dehumidified. This extra moisture in the air encourages mold growth. To fix it without replacing your unit, invest in a dehumidifier.

 

If your air conditioning unit is emitting an unpleasant, musty smell, contact the experts at Illy HVAC in St. Peters, MO. For more than 30 years, this locally owned and operated company has helped local homeowners fix a variety of HVAC issues. They will perform a professional inspection to diagnose the problem and provide you with fast and reliable repairs. Schedule an appointment by calling (314) 808-2162, or learn more about their services online.