When your air conditioner starts spewing strange or unappealing odors, it is necessary to take notice because it could be a sign of a significant problem. Disregarding unpleasant smells coming from your air conditioner could lead to additional damage to your HVAC system or even pose a risk to your health and safety.

Depending on the smell, the culprit may be bacteria or fungus in the system. In other cases, it could also signal something mechanically wrong with the air conditioner. Some smells are even indicative of a dangerous situation, like a natural gas leak.

At Controlled Comfort HVAC, we are skilled at diagnosing and fixing these type of problems. If you smell something odd coming from your cooling system, there's a good chance our team of talented professionals has smelled it, too—and fixed it! We’ve earned the reputation as the go-to team for air conditioning repair in Carpentersville.

What does a specific odor coming from your air conditioning mean? Here are some common air conditioner odors and what they could mean:

My Air Conditioner Smells Like Feet

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

Another likely reason for an odor of stinky feet could be a dirty air filter. When your HVAC system's air filter becomes choked with dirt, dust and other debris, it can lead to low air quality and a musty smell that bears a resemblance to feet.

To solve 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 change the air filter regularly to promote good air quality and restrict the growth of bacteria and fungus.

My Air Conditioner Smells Like Rotten Eggs

If your smells like rotten eggs, it might be due to a natural gas leak in the unit or in the surrounding area. Natural gas has a unique 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 very 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, evacuate the building and call your gas company or emergency services right away.

My Air Conditioner Smells Like Mildew

If your air conditioner emits a smell like mildew, it might be due to a collection of moisture inside the unit. When moisture collects inside a cooling system, it can promote the growth of mold and mildew. This can cause a musty stench that bears a resemblance to mildew.

Another possible reason for the smell might be a soiled air filter. Once the air filter becomes clogged, it can result in poor air quality and a musty smell that is similar to mildew.

Regular air conditioning maintenance from Controlled Comfort HVAC can help avoid both of these situations, because a good cleaning, inspection and filter change is a terrific way to keep your system working at its best!

My Air Conditioner Smells Like Urine

One of the most unpleasant scenarios is when your AC smells like urine.

If your air conditioning equipment reeks of urine, it could be due to a variety of factors. One potential cause is a accumulation of bacteria or mold in the your HVAC. This can happen when moisture accumulates in the system and creates a moist environment that is conducive to bacterial growth. The bacteria can create a foul odor that some people describe as smelling like urine.

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

My Air Conditioner Smells Like Burning Plastic

If your air conditioning system smells like burning plastic, this could indicate an electrical problem with the unit. After some time, the electrical parts in the air conditioning system can wear out or break, which can make a burning smell that resembles plastic.

Another possible cause of the smell could be a foreign object lodged in the HVAC system. If something foreign gets trapped in the air conditioning system, it can heat up and result in a smell that reminds people of burning plastic.

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

My Air Conditioner Smells Like Gas

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

As we said before, 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, evacuate the building and phone your gas company or emergency services as soon as possible.

Why My Air Conditioner Smells Like Fish

If 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 creates an environment that is conducive to 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 cause a smell like dirty feet.

Another plausible explanation for the smell could be a dead animal or other biological material stuck within the air conditioning system. This often can happen if an animal such as a mouse or bird gets trapped inside the unit and dies.

To fix the issue, it's worthwhile to have a professional check out and clean your HVAC system. They should be able to find the source of the smell and take the proper steps to remove any contaminants and keep the problem from recurring.

Why My Air Conditioner Smells Like Vinegar

There could be numerous reasons your AC smells like vinegar. One possible cause is a dirty air filter. One other likely cause of the smell may be a refrigerant leak. If the refrigerant leaks, it can make a chemical odor that resembles vinegar.

To fix the issue, it's beneficial to have a skilled tech examine and clean your air conditioning.  If the odor lingers after the cleaning and changing of the air filter, it's best to reach back out to a professional to find and repair any hidden 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, Controlled Comfort HVAC can help locate the ideal unit to fit your home’s needs. We provide dependable, skilled air conditioner installation in Carpentersville.

My Air Conditioner Smells Like Chemicals

If the smell of chemicals is coming from your air conditioning equipment, it could be caused by a refrigerant leak. When the refrigerant leaks, it can create a chemical odor that is often described as smelling like chemicals or paint thinner, vinegar or acetone.

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

If you suspect a refrigerant leak or an electrical concern, it's important to shut off your air conditioning system right away and contact a professional to inspect and repair the unit. Refrigerant leaks can be dangerous and may require immediate attention to avoid injury or damage to your home.

Strange Smell Coming from Your AC? Call the Pros at Controlled Comfort HVAC

If your air conditioner stinks and you aren’t able to fix it smoothly on your own, reach out to the cooling professionals at Controlled Comfort HVAC. We have lots of experience working with a wide variety of HVAC systems. Our crew has fixed many air conditioning problems throughout the years—including funky smells. Call us today for quality AC repair in Carpentersville!