Reasons Why Your Air Conditioner Smells Bad

Reasons Why Your Air Conditioner Smells Bad
Your air conditioner is designed to remove moisture that usually is friendly for mold.
It is also designed to filter any allergens out of the air before they enter your home. However, if you are not keeping the filter clean or the air conditioner itself, it may cause the unit to become extremely funky.

Why the Air Conditioner Stinks

As humans, we naturally shed our skin. These are called skin squames. These squames are sucked into the air conditioner.
Once they are in the unit, these skin pieces are food for bacteria. (Your unit will always have bacteria, however, depending on how much you clean it, it may have less than others.) When the bacteria eat this skin and digest the proteins found in the skin, they produce the smell that is not so pleasant.
The smell may smell like ammonia or even urine. It may also smell like body odor. Keep in mind that bad smells can impact your life. It is important to have a good filter in the system. Skin squames are bigger than ten micrometers. You should find a filter that can capture these small particles. If you do that, your odor problem should improve. You may also want to vacuum more frequently. Your vacuum should be a sealed vacuum with a certified HEPA filter.

Other Smells You May Notice

We are going to talk about a few other smells that you may notice and what to do if you notice a certain smell. The above smell is simply a cleaning problem. However, these smells could point to a more serious problem. These tips are for central air conditioning units and the above is for both central and window units.
  • Leaks
  • Skunk
  • Stinky Feet
  • Sewage
  • Rotten Eggs
  • Mildew
  • Carbon or Gun Powder
  • Exhaust
If you notice a scent of skunk when you run your air conditioner and cannot find the source even after a good clean, then you should take a look at your gas system. There is a compound added to natural gas and propane that helps you detect leaks sooner.
This is a damp musty smell that is mixed with the smell of wet leaves. If this is the odor your air gives off, it may be water that has not drained from your HVAC system. You should simply be able to drain the water and give it a good cleaning to solve the problem.
Sewer lines smell the way they do because they have methane gasses. If you are smelling this in your home, you may have a problem with a ruptured sewer. Methane will eventually seep into your system and be noticed throughout your home. If methane is large enough, it can cause explosions and be harmful to you.


No one likes to smell rotten eggs; this is especially true if it is coming from your air conditioning unit. If you notice this smell, you likely have a dead animal somewhere in your ventilation system. Sometimes this animal can be a small rodent or even a bird if they are sick. Once they enter, they are unsure how to exit and die.
If you notice a fungus-like odor filling the home when you run your air conditioning unit, it is likely mold or mildew in your system. Keep in mind that HVAC systems are not just responsible for the temperature. HVAC systems also help control moisture and humidity. They even filter the air.

Electrical Issues

When you notice something smoking it is signs that are visual. You will not mistake these signs and they can be traced pretty easily. However, when you have an onboard motor and it burns out or a circuit board that shorts, your smoke will smell more like gun powder. If this happens to you, you will not notice the natural fire smoke smell.
Keep in mind that electricity powers our air conditioning units. Even though this is stated, some fluids can still leak. The fluids that leak, will oftentimes smell like exhaust fumes. If you smell this, you should have your unit inspected.
Once you have your air conditioning in top-notch shape, your home could be filled with these lingering odors.

Leave a comment