Why Does My AC Smell Like Mildew?

If you turn on your air conditioning system only to smell the musty smell associated with mold and mildew growth it can certainly put a damper on your mood. Air conditioning should be refreshing and comfortable, but otherwise undetectable. The only thing more miserable than dealing with the hot, sticky conditions is dealing with a foul smell coming from your air conditioning vents.

If you AC smells like mildew, mold, or other foul odors, it is time to troubleshoot the problem and perhaps call for professional assistance.

Common Causes For Mildew Smell From Your AC

Mold and mildew odors are some of the most common odors found in air conditioning duct work and they can occur for a variety of reasons. A properly functioning air conditioning system should overcome the presence of moisture–the building blocks for mold and mildew growth.

Here are the most common causes for mildew odors to occur in HVAC systems:

  • Dirty or Clogged Filters – If your filter is dirty, clogged, or gets too much exposure to moisture, mildew can begin to grow. Filters trap tiny organic particles that can accelerate mildew growth when exposed to moisture. Check your filters first and if they appear dirty, replace them.
  • Clogged Drip Pan – If your drip pan is clogged, is filling too fast, or has been moved and is no longer positioned where it should be, this can cause mildew growth in and around your air conditioning system. If it is a simple visible clog, you can likely remedy this problem yourself, but more extensive problems may require professional assistance.
  • Clogged Condensate Drain Line – The condensate drain line runs from the coils to the outside of the AC unit and removes condensation created by the coils. If it is clogged, mildew may accumulate on and around your coils.
  • Moist Ductwork – This can occur if your ducts are not well sealed or if your AC system is not removing moisture from the air as well as it should. Excess moisture in your ducts can lead to mold and mildew growth, then spread that odor throughout your house until the source of the moisture is address.
  • Internal Problems – Sometimes, the interior parts of your air conditioning system may be dirty or have mildew growth. If you have already addressed the other possible causes above with no success, it is time to call an HVAC technician that can better diagnose and fix your problem.

When You Need Professional Assistance

If you’ve tried the easy DIY solutions like changing your air filters and checking the drip pan for visible clogs with no success, it is time to contact a professional HVAC technician. Many people will first opt to have their ductwork cleaned, but this is simply masking the problem if the underlying cause is not identified. Your technician can survey the situation to determine if an underlying problem needs to be fixed so the smell doesn’t keep coming back.

Schedule AC Repair Service in Philadelphia Today

For help with a mildew smell from the air conditioner in Philadelphia, call the experts at W.F. Smith to clean and fix the problem.

Everyone, with whom I had personal or telephone contact, was agreeable, helpful and informative. Justin was the service person who initially diagnosed the problem, and represented Smith’s during the sales transaction. Shelly was my telephone contact, and Bill and Aaron did the install. Each person was professional and knowledgeable. Thanks,