When your air conditioner starts spewing strange or unappealing smells, it is a good idea to take notice because it could be a sign of a major problem. Dismissing unpleasant smells coming from your air conditioning can lead to additional damage to your air conditioning or even pose a risk to your health and safety.

Depending on the smell, the cause might be bacteria or fungus in the system. In other cases, it could also signal something mechanically wrong with the AC. Some smells are a sign of a harmful scenario, like a natural gas leak.

At US Air Heating and Cooling, we are skilled at diagnosing and fixing these type of problems. If you smell something peculiar coming from your cooling system, chances are our team of qualified professionals has smelled it, too—and fixed it! We’ve earned the reputation as the premier company for air conditioning repair in Rock Hill.

What does a specific odor wafting coming from your AC mean? Here are several frequent air conditioner aromas and what they may mean:

My Air Conditioner Smells Like Feet

If your air conditioner smells like feet, it may be because of a buildup of bacteria or fungus in the unit. When moisture accumulates inside the unit, it can create an environment that is conducive to the development of bacteria and fungus. This can result in a foul odor that is often described as smelling like dirty feet.

Another likely explanation for an odor of stinky feet may be a dirty air filter. If an air filter becomes choked with dirt, dust and other contaminants, it can result in substandard air quality and a musty smell that it similar to the smell of feet.

To fix this unpleasant situation, it's important to have an experienced specialist 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 routinely to ensure good air quality and protect against the formation of bacteria and fungus.

My Air Conditioner Smells Like Rotten Eggs

If your air conditioner reeks of rotten eggs, it could be the result 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 a situation that 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 ventilate the area, evacuate the building and call your gas company or emergency services right away.

My Air Conditioner Smells Like Mildew

If your AC is giving off an odor like mildew, it could be due to a buildup of moisture inside the unit. When moisture forms inside the air conditioning system, it can cultivate the growth of mold and mildew. This can cause a musty odor that resembles mildew.

Another possible explanation for the smell might be a clogged air filter. Once the air filter becomes clogged, it can result in poor air quality and a musty smell that has a resemblance to mildew.

Routine air conditioning maintenance from US Air Heating and Cooling can help protect against both of these problems, because a good cleaning, inspection and filter change is a terrific way to keep your system running at its best!

My Air Conditioner Smells Like Urine

One of the most undesirable scenarios is when the air coming out of your HVAC system smells like urine.

If your air conditioning equipment smells like urine, it could be due to a variety of factors. One possible cause is a buildup of bacteria or mold in the air conditioning system. This can happen if moisture accumulates in the system and creates a wet environment that is conducive to bacterial growth. The bacteria can emit a foul odor that it similar to urine.

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

My Air Conditioner Smells Like Burning Plastic

If your air conditioning system smells like burning plastic, a possible cause could be an electrical problem with the unit. Over time, the electrical elements in the air conditioning system can wear out or malfunction, 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 HVAC system. If something foreign gets caught in the air conditioning system, it can become hot and cause a smell like burning plastic.

If you smell burning plastic coming from your cooling system, it’s worthwhile to call a professional right away.

My Air Conditioner Smells Like Gas

If your air conditioning smells like gas, there could be a natural gas leak in the unit or in the surrounding area. Natural gas has a recognizable smell, often described as smelling like rotten eggs or sulfur. That’s because this scent is incorporated into natural gas so that it is easily detectable.

As we said previously, a natural gas leak can be VERY dangerous and needs 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 phone your gas company or emergency services as soon as possible.

Why My Air Conditioner Smells Like Fish

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

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

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

Why My Air Conditioner Smells Like Vinegar

There could be several reasons an air conditioning system smells like vinegar. One possible cause is a clogged air filter. A second possible cause of the smell may be a refrigerant leak. If the refrigerant leaks, it can make a chemical odor that is described as smelling of vinegar.

To fix the issue, it's essential to have a skilled specialist look at and clean your air conditioning.  If the odor lingers 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, the mechanic can tell you if your air conditioning ought to be replaced.

If you are wanting to upgrade, US Air Heating and Cooling can help select the right unit to fit your home’s needs. We deliver trustworthy, expert air conditioner installation in Rock Hill.

My Air Conditioner Smells Like Chemicals

If the smell of chemicals is coming out of your air conditioning equipment, it could be caused by a refrigerant leak. In a situation where the refrigerant leaks, it can create a chemical scent that some people describe as smelling like chemicals or paint thinner, vinegar or acetone.

One other possible source of the smell could be an issue with the electrical wiring or hardware inside the air conditioning system. This can result in a burning smell that resembles chemicals or burning plastic.

If you believe there is a refrigerant leak or an electrical problem, it's important to turn off your air conditioning system right away and contact a professional to inspect and repair the unit. Refrigerant leaks can be hazardous and may require immediate attention to prevent injury or damage to your residence.

Strange Smell Coming from Your AC? Call the Pros at US Air Heating and Cooling

If your air conditioner smells nasty and you aren’t able to fix it smoothly on your own, reach out to the cooling specialists at US Air Heating and Cooling. We have years of experience working with a wide variety of air conditioning systems. Our crew has fixed many air conditioning concerns over the years—including weird smells. Call us today for quality AC repair in Rock Hill!