A Musty Smell When the House Air Conditioner Runs


Knowing how to troubleshoot and repair your home appliances can save you lots of valuable time and money in the long run. By identifying and diagnosing potential problems with your appliances, you can know whether or not you can fix a problem on your own, thereby saving even more money, of if you will need to hire a professional. If you notice a musty or mildewy smell emanating from your air conditioner when it is running, you can troubleshoot the problem with only a few basic steps.

Water Pads

  • Evaporative cooling air conditioners, sometimes known as swamp coolers, use moistened pads placed in front of a fan to cool air as it is circulated throughout a room. The older the pads get, the less resistance they have to mildew buildup. Since every bit of air that the swamp cooler forces out has to first pass through the moist pad, the cool air being forced out of the air conditioner will carry the odor of built up mildew on it. The Consumer Energy Center of the California Energy Commission recommends changing these pads every warm season, or at the least every other warm season. Even if they are not the cause of the mildew smell, replacing the pads greatly increases the efficiency of your swamp cooler and saves on long-term energy costs.

Outside Air

  • Similarly, if the air the swamp cooler is pulling in from the outside is muggy and moist, the dampness of the air can impart the moist pads with a mildewy or musty smell that travels throughout the house. Unfortunately, since this problem is caused by outside weather conditions, there really is no solution to this particular problem except to use an alternate method of cooling that does not draw in outside air.

Central Air Conditioning Problems

  • If you use a central air conditioning system rather than evaporative coolers, finding the source of a musty smell is made more difficult by the size of the AC unit and its many parts.Troubleshooting central units follows a similar principle to troubleshooting evaporative coolers; if the air being forced through the system comes into contact at any time with a mildewy smell, the smell will accompany the air through the entire house. First, make sure there is no mildew on the outside air conditioning unit or on the air conditioning filter. Replace old filters, especially if they are overly damp. Other parts of the AC system that are prone to mildew growth are the air handler, the condensate drain, the drain pan and drain line.

Other Possible Causes

  • Check all over your home for any mold or mildew growth. They can both be difficult to find, but the Florida Department of Health recommends checking "walls, ceilings, or anything made of wood or paper" for anything "cottony, velvety, rough or leathery" that is colored "white, gray, brown, black, yellow, or green." Also check the house for any ceiling leaks or other water leakage, as this is one of the primary causes of mildew proliferation.

Related Searches


Promoted By Zergnet


You May Also Like

Related Searches

Check It Out

22 DIY Ways to Update Your Home on a Small Budget

Is DIY in your DNA? Become part of our maker community.
Submit Your Work!