Harkins AC, Heating, & Controls

The Cause Of These 5 Common AC Odors

Why Does My AC Smell Bad?

If strange odors are coming from your air conditioner, there’s something wrong. Most people report smelling “dirty socks” or “rotten eggs” from  their AC. Some reasons for these smells include mold, mildew, and broken parts.

Common AC Odors & The Reason For Them

  1. Moldy or Musty – A smell of mold, while your A/C is running, is one of the common odors that it emits. What causes this musty smell is the moisture that did not drain properly. When condensation within the unit is too much, it can go directly to the ductwork resulting in mold buildup. Cleaning the ducts and eliminating the mold solve the musty smell. Contact your HVAC contractor to handle the issue for you.
  2. Rotten Eggs – If the air coming from your air conditioning unit smells like rotten eggs, the possible cause could be decaying insects or animals. A rodent or bird might have crawled into the ducts and did not find a way out. When they decompose, a disgusting smell will surely make everyone in the house uncomfortable and sick. Remove the animal as early as now to avoid serious effects on your family’s health.
  3. Gunpowder – Does your A/C smell like a wire or rubber is burning? Watch out because your unit may be overheating or having electrical problems. Commonly, gunpowder odor is caused by a short circuit in the wiring or overheating of the motor. To check on the problem, ask the help of professionals for assistance especially if it involves repair or replacement.
  4. Exhaust Fumes – The odor of exhaust fumes from your A/C unit does not indicate inconvenience but danger as well. The fact that air conditioners are run by electricity, the exhaust is a warning sign of fluid leaks from the motor. A visual inspection can determine what really causes this exhaust fume smell. It is best to contact your HVAC technician to inspect or repair your unit if needed.
  5. Dirty Socks – Are you familiar with the dirty sock syndrome? Many homeowners complain about the unpleasant, stinky odor from their A/C unit without knowing what causes the smell. Dirty sock syndrome is caused by mold, dirt buildup, bacteria and other particles hiding in your system. To eliminate the odor you can either buy a germicidal product or hire a professional cleaning service.


Is one of these odors overpowering your home? Call the experts at Harkins Air Conditioning immediately! One of our highly skilled HVAC technicians can fix it!