When your air conditioner starts putting out odd or gross aromas, it is necessary to take notice because it could be a sign of a big problem. Dismissing unpleasant smells coming from your air conditioner may lead to further damage to your air conditioning or even pose a risk to your health and safety.

Depending on the cause of the odor, the root of the problem could be bacteria or fungus in the system. Other times, it could also sign something mechanically wrong with the AC. Some smells are a sign of a dangerous situation, like a natural gas leak.

At May's Heating & Air, we are experienced at getting to the root cause of stinky smells. If you smell something peculiar coming from your AC, you can bet that our team of talented professionals has smelled it, too—and fixed it! We’ve earned our reputation as the first call for air conditioning repair in Frederick.

What does a particular smell wafting coming from your AC mean? Here are several common air conditioner odors 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 system. When moisture accumulates inside the unit, it can establish an environment that is favorable to the spread of bacteria and fungus. This can produce a foul odor that is often described as smelling like feet.

Another possible cause of the smell might be a dirty air filter. If an air filter becomes clogged with dirt, dust and other debris, it can result in low air quality and a musty smell that resembles feet.

To fix this issue, 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 exchange the air filter on a regular basis to ensure good air quality and prevent the formation of bacteria and fungus.

My Air Conditioner Smells Like Rotten Eggs

If your air conditioner stinks like rotten eggs, it may be the result of a natural gas leak in the unit or in the surrounding area. Natural gas has a distinct odor, often described as smelling like rotten eggs or sulfur, that 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 air out the area, make everyone leave the building and call your gas company or emergency services right away.

My Air Conditioner Smells Like Mildew

If your cooling system emits a smell like mildew, it may be due to a collection of moisture inside the unit. When moisture forms inside the air conditioning system, it can foster the growth of mold and mildew. This can cause a musty stench that resembles mildew.

Another possible cause of the smell may be a soiled air filter. When the air filter becomes clogged, it can cause poor air quality and a musty smell that resembles mildew.

Routine air conditioning maintenance from May's Heating & Air 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 scenarios is when an air conditioner smells like urine.

If your air conditioning reeks of urine, it could be traced back to a number of things. One potential cause is a accumulation of bacteria or mold in the air conditioning system. This can happen when moisture accumulates in the system and creates a moist environment that can promote bacterial growth. The bacteria can create a foul odor that is like urine.

Another potential cause of the scent of urine could be a blocked drain line. The condensation that forms inside the air conditioning unit needs to drain away correctly, 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 can stink like urine.

My Air Conditioner Smells Like Burning Plastic

If your air conditioning system smells like burning plastic, it might be because of an electrical problem with the unit. After some time, the electrical elements in the air conditioning system can wear out or bust, which can produce a burning smell that resembles plastic.

Another possible reason for the smell could be a foreign object stuck in the unit. If something foreign gets trapped in the air conditioning system, it can heat up and result in a smell similar to burning plastic.

If you notice something that smells like burning plastic coming from your cooling system, it’s important to call a professional right away.

My Air Conditioner Smells Like Gas

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

As mentioned earlier, a natural gas leak can be VERY dangerous and calls for immediate attention. Should you suspect a gas leak, turn off your air conditioning system, open windows and doors to air out the home, leave the building and call your gas company or emergency services as soon as possible.

Why My Air Conditioner Smells Like Fish

Should your air conditioner smell like fish, you may have a situation where there's a build-up of bacteria or mold in the unit. Moisture causes an environment that fosters the growth of bacteria and mold. This can cause a disgusting odor that is sometimes described as smelling like fish or, as mentioned earlier, it also can cause a smell like dirty feet.

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

To fix the issue, it's worthwhile to have a professional inspect and clean your HVAC system. They can find the source of the smell and take the proper steps to remove any contaminants and stop the problem from recurring.

Why My Air Conditioner Smells Like Vinegar

There could be numerous reasons your air conditioner smells like vinegar. One possible cause might be a plugged air filter. Another possible cause of the smell could be a refrigerant leak. Sometimes after 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 mechanic look at and clean your air conditioning.  If the odor continues after the cleaning and replacing of the air filter, it's best to reach back out to a professional to identify and repair any underlying issues with your air conditioning. Or, the mechanic can tell you if your air conditioning needs to be replaced.

If you are wanting to upgrade, May's Heating & Air can help find the right unit to fit your home’s needs. We deliver trustworthy, skilled air conditioner installation in Frederick.

My Air Conditioner Smells Like Chemicals

If the smell of chemicals is coming out of your air conditioning equipment, it could be the result of 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.

An additional possible cause of the smell could be a problem with the electrical wiring or components inside the air conditioning system. This can produce a burning smell that resembles chemicals or burning plastic.

If you think your system has a refrigerant leak or an electrical concern, it's important to turn off your air conditioning system as soon as possible and contact a professional to inspect and repair the unit. Refrigerant leaks can be harmful and may require immediate attention to protect against injury or damage to your residence.

Strange Smell Coming from Your AC? Call the Pros at May's Heating & Air

If your air conditioner reeks and you aren’t able to fix it quickly on your own, contact the cooling professionals at May's Heating & Air. We have lots of experience working with a wide variety of air conditioning systems. Our crew has fixed many air conditioning concerns through the years—including funky smells. Call us today for quality AC repair in Frederick!