Why does my AC smell? Home Improvement by Kathleen Debra - January 21, 20190 You may notice that whenever your AC is on, it emits an unpleasant odor. Some of us will question if it is normal. The answer is yes and no. Air conditioners do smell, but not unpleasantly. If you do notice foul smells coming from your unit, you need to call for your technician. Following are some of the possible reasons why your AC is smelling bad It could be mold on evaporator coils Warm air passes over the cold coils leading to condensation. If dirt happens to settle there, then that is a perfect breeding ground for bacteria like mold. Again, you will realize some ice forming on some coils. This results to weaker airflow than normal and therefore, you have to thoroughly clean the system. This calls for a professional technician. Mold in ductwork Sometimes, there could be mold in the ductwork, which might have been caused by leaks in the air ducts, high humidity levels inside the room, or mold growth that has spread from another source. You have to visually inspect the ducts on a routine basis. To ensure cleanness in the ducts, the ordinary eye may not succeed; therefore, you need an expert to do the work. Clogged condensate drain line When condensation drips off the evaporator coils, the condensate drain line is responsible for draining. If the system is clogged, the trapped water is likely to lead to bacteria and mold growth. Too much of this may shut off your AC system. Therefore, you need to look for an aircon repair service professional to unclog the lines and allow free airflow. Poor aeration Once in a while, you need to allow free airflow from outside the building. This helps in clearing the dump smelling air from the system and therefore, allowing fresh air. Ensure your windows are opened during the daytime and remove any obstruction from the ventilators. A bad smelling environment can be very discomforting and unhealthy. Therefore, you should always be aware and look out for any signs of clogging. When that occurs, engage a qualified professional to properly address the airflow obstruction.