Rotten Egg Smell When Air Conditioner Runs

Causes

• Air conditioners remove humidity from the air that goes inside the unit. This moisture collects on the base of the air conditioner. The moisture normally evaporates, but in very rainy weather or high humidity, this may not be possible. The moisture stagnates with lint, dust and other debris on the base, resulting in mold and mildew growth. Another cause of condensation build-up is a clogged drain hole that prevents the water from draining out of the unit.

Cleaning the Air Conditioner

• Unplug the air conditioner unit or turn off the power at the breaker. Remove the cover from the unit so you can see inside the base. Wipe out any water, dirt and debris with paper towels. Wash out the base with warm soapy water and a sponge. Rinse the base well with another damp -- not dripping -- sponge. Dry the base with a dry cloth and replace the cover.

Clearing Clogged Drain Holes

• Water in a clogged drain hole stagnants with other debris and causes musty or rotten-egg odors. Remove the screws from the front grill on the air conditioning unit. You may have to pull the unit partially out of the window in order to see the drain hole. Straighten a wire clothes hanger and stick one end into the drain hole to remove the clog by inserting the hanger and removing it two or three times. Another option is to use a bulb baster filled with water to flush it out. Remove all the excess water with paper towels, clean the area and replace the grill.

Prevention

• Cleaning your air conditioner at least once a year is an effective way to prevent odors. This also allows the air conditioner to run more efficiently, thus reducing electric bills. Replacing the filters or cleaning them is another way to ensure the long life of your air conditioning unit. If you have central air conditioning, hire a professional to clean and inspect the unit annually. He can spot and fix any potential problems after thoroughly cleaning the unit.