When your air conditioner starts spewing odd or gross smells, it is a good idea to take notice because it could be a sign of a significant problem. Dismissing unpleasant smells coming from your cooling system can lead to further damage to your HVAC system or even pose a risk to your health and safety.

Depending on the cause of the odor, the cause may be bacteria or fungus in the system. In other cases, it could also sign something mechanically wrong with the air conditioning system. Some smells are a sign of a hazardous scenario, such as a natural gas leak.

At Kohles & Bach Heating & Cooling, we have a nose for these sorts of things. If you smell something odd coming from your air conditioner, there's a good chance our team of qualified professionals has smelled it, too—and fixed it! We’ve earned our reputation as the go-to team for air conditioning repair in Des Moines.

What does a certain smell coming coming from your cooling system mean? Here are several frequent air conditioner odors and what they might mean:

My Air Conditioner Smells Like Feet

If your air conditioner smells like feet, it could be because of a buildup of bacteria or fungus in the unit. When moisture accumulates inside the unit, it can produce an environment that is favorable to the growth of bacteria and fungus. This can result in a nasty odor that is often described as smelling like feet.

Another likely explanation for an odor of stinky feet may be a dirty air filter. When the air filter becomes filled with dirt, dust and other contaminants, it can lead to poor air quality and a musty smell that it similar to the smell of feet.

To correct this dilemma, it's important to have a professional inspect and clean your air conditioning system, including the evaporator coil, drain pan and condensate drain line. It's also important to change the air filter on a regular basis to ensure good air quality and protect against the growth of bacteria and fungus.

My Air Conditioner Smells Like Rotten Eggs

If your air conditioning equipment reeks of rotten eggs, it could be because of a natural gas leak in the unit or in the surrounding area. Natural gas has a distinctive odor, often described as smelling like rotten eggs or sulfur, which is added to it to make it easily detectable.

A natural gas leak is extraordinarily dangerous and requires immediate attention. If you suspect a gas leak, turn off your air conditioning system, immediately open windows and doors to allow gas to escape the area, get everyone out of the building and call your gas company or emergency services immediately.

My Air Conditioner Smells Like Mildew

If your cooling system is giving off an odor like mildew, it might be due to a collection of moisture inside the unit. When moisture collects inside the air conditioning system, it can cultivate the growth of mold and mildew. This can cause a musty stench that resembles mildew.

Another possible explanation for the smell may be a dirty air filter. When the air filter becomes clogged, it can cause poor air quality and a musty smell that has a resemblance to mildew.

Routine air conditioning maintenance from Kohles & Bach Heating & Cooling can help avoid both of these situations, because a good cleaning, inspection and filter change is a great way to keep your system working at its best!

My Air Conditioner Smells Like Urine

One of the most distressing things is when an air conditioner smells like urine.

If your air conditioner stinks like urine, it could be due to a variety of factors. One likely cause is a accumulation of bacteria or mold in the your cooling system. This can happen when moisture accumulates in the system and creates a moist environment that is conducive to bacterial growth. The bacteria can produce a foul odor that it similar to urine.

Another potential cause of the stink could be a blocked drain line. The condensation that forms inside the air conditioning unit needs to drain away effectively, but if the drain line becomes filled with debris, it can cause water to back up and collect inside the unit. This can produce a musty smell that resembles urine.

My Air Conditioner Smells Like Burning Plastic

If your AC smells like burning plastic, a possible cause could be an electrical problem with the unit. After a while, the electrical parts in the air conditioning system can wear out or break, which can make a burning smell that resembles plastic.

Another possible root cause of the smell could be a foreign object that somehow got in the unit. If something foreign gets trapped in the air conditioning system, it can become hot and emit a smell like burning plastic.

If you think you smell burning plastic coming from your AC unit, it’s important to contact a professional right away.

My Air Conditioner Smells Like Gas

If your air conditioner smells like gas, it could be due to a natural gas leak in the unit or in your home. Natural gas has a distinct aroma, often described as smelling of rotten eggs or sulfur. That’s because a smell is incorporated into natural gas to make sure that it is easily detectable.

As mentioned before, a natural gas leak can be VERY hazardous and calls for immediate attention. When you suspect a gas leak, turn off your air conditioning system, open windows and doors to air out the home, evacuate the building and call your gas company or emergency services right away.

Why My Air Conditioner Smells Like Fish

Should your AC smell like fish, it could be due to a build-up of bacteria or mold in the unit. Moisture creates an environment that fosters the growth of bacteria and mold. This can cause a foul odor that is often described as smelling like fish or, as mentioned earlier, it also can result in a smell like dirty feet.

Another possible cause of the smell could be a dead animal or other biological material stuck inside the air conditioning system. This often is possible if an animal such as a mouse or bird gets trapped inside the unit and dies.

To fix the issue, it's often necessary to have a professional examine and clean your cooling system. They should be able to determine the source of the smell and take the correct steps to remove any contaminants and prevent the problem from recurring.

Why My Air Conditioner Smells Like Vinegar

There could be numerous reasons a home's air conditioner smells like vinegar. One possible cause of the smell could be a clogged air filter. A second potential cause of the smell could be a refrigerant leak. If the refrigerant leaks, it can create a chemical odor that is described as smelling of vinegar.

To fix the issue, it's important to have a skilled mechanic look at and clean your air conditioning.  If the odor continues after the cleaning and exchanging the air filter, it's best to reach back out to a professional to find and repair any persistent issues with your air conditioning. Or, they can tell you if your air conditioning ought to be replaced.

If you are looking to upgrade, Kohles & Bach Heating & Cooling can help find the right unit to fit your home’s needs. We deliver dependable, professional air conditioner installation in Des Moines.

My Air Conditioner Smells Like Chemicals

If the smell of chemicals is coming from your air conditioning equipment, it could be due to a refrigerant leak. If the refrigerant leaks, it can create a chemical odor that some people describe as smelling like chemicals or paint thinner, vinegar or acetone.

An additional possible reason for the smell could be a problem with the electrical wiring or components inside the air conditioning system. This can cause a burning smell that it similar to chemicals or burning plastic.

If you believe there is a refrigerant leak or an electrical issue, it's important to shut off your air conditioning system immediately and contact a professional to inspect and repair the unit. Refrigerant leaks can be hazardous and may require immediate attention to protect against injury or damage to your house.

Strange Smell Coming from Your AC? Call the Pros at Kohles & Bach Heating & Cooling

If your air conditioner stinks and you aren’t able to fix it quickly on your own, call the cooling specialists at Kohles & Bach Heating & Cooling. We have years of experience working with a wide variety of air conditioning systems. Our crew has fixed many air conditioning problems throughout the years—including strange smells. Call us today for quality AC repair in Des Moines!