Why Would an Air-Conditioner Emit a Mildewy Odor?

The smell of mildew coming from your air-conditioner is more than just unpleasant. It is a warning that your air-conditioning unit needs maintenance to take care of a mold problem.

Cause

Your air-conditioner emits a mildewy odor because mold is growing inside of it. The condenser coil in your air-conditioner is in a moist environment. If the condenser pan does not drain properly, then too much moisture encourages mold growth on the coil. The air-conditioner then blows mold spores and the smell of mildew into your home when it runs.

Solution

Removing the mold will take care of the bad odor. You can clean the condenser coil using a mixture of 1/2 cup of bleach in 1 gallon of water. Use the solution and a sponge to wipe the coil clean. Wear gloves and eye protection while you work. Afterward, make sure the condenser pan allows water to drain so moisture cannot build up again.

Considerations

Ignoring the mildew odor coming from your air-conditioner is a mistake. Over time, mold spores will be blown through the air ducts in your home. If they settle and grow inside the ducts, you will need the help of a professional mold remediator to remove this potential health hazard from your home.

References

• "Recognition, Evaluation and Control of Indoor Mold"; Bradley Prezant, Donald M. Weekes, J. David Miller; 2008