When your air conditioner starts putting out unusual or unappealing smells, it is important to take notice because it could be a sign of a major problem. Dismissing unpleasant smells coming from your air conditioning can lead to serious damage to your HVAC system or even pose a risk to your health and safety.

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

At AZ Air Conditioning and Heating, we are experienced at getting to the root cause of stinky smells. If you smell something weird coming from your air conditioner, you can bet that our team of skilled pros has smelled it, too—and fixed it! We’ve earned the reputation as the premier company for air conditioning repair in Los Angeles.

What does a certain smell billowing out of your AC mean? Here are several frequent air conditioner smells and what they could mean:

My Air Conditioner Smells Like Feet

If your air conditioner smells like feet, it might be due to a buildup of bacteria or fungus inside of it. When moisture accumulates inside the unit, it can produce 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 stinky feet.

Another potential reason for an odor of stinky feet may be a dirty air filter. When your HVAC system's air filter becomes filled with dirt, dust and other debris, it can cause 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 routinely to provide good air quality and prevent the growth of bacteria and fungus.

The Air Conditioning Smells Like Rotten Eggs

If your air conditioning unit reeks of rotten eggs, it might 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 extremely 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, make everyone leave the building and call your gas company or emergency services right away.

Your AC Smells Like Mildew

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

Another possible cause of the smell may be a soiled air filter. If the air filter becomes clogged, it can result in poor air quality and a musty smell that is similar to mildew.

Annual air conditioning maintenance from AZ Air Conditioning and Heating can help avoid both of these problems, because a good cleaning, inspection and filter change is a terrific way to keep your system working at its best!

The Air Conditioning Smells Like Urine

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

If your air conditioning stinks like urine, it could be traced back to a number of things. One possible cause is a accumulation of bacteria or mold in the your HVAC. This can happen in the event that moisture accumulates in the system and creates a wet environment that is conducive to bacterial growth. The bacteria can produce a foul odor that resembles urine.

Another feasible cause of the smell could be a plugged drain line. The condensation that forms inside the air conditioning unit needs to drain away properly, but if the drain line becomes stopped up by debris, it can cause water to back up and accumulate 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, a possible cause could be an electrical concern with the unit. After a while, the electrical elements in the air conditioning system can wear out or break, which can produce a burning smell that resembles plastic.

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

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

The Air Conditioning Smells Like Gas

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

As stated previously, 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, leave the building and contact your gas company or emergency services straight away.

The Air Conditioning Smells Like Fish

If your AC smell like fish, it could be due to a build-up of bacteria or mold in the unit. Moisture produces an environment that promotes the growth of bacteria and mold. This can cause a strong odor that can be 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 caught inside 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 solve the issue, it's worthwhile to have a professional inspect and clean your air conditioning system. They can determine the source of the smell and take the proper steps to remove any contaminants and keep the problem from recurring.

Your AC Smells Like Vinegar

There could be numerous reasons your air conditioning system smells like vinegar. One possible cause might be a dirty air filter. Another possible cause of the smell might be a refrigerant leak. Sometimes after the refrigerant leaks, it can generate a chemical odor that is similar to vinegar.

To fix the issue, it's beneficial to have a skilled tech look at and clean your air conditioning.  If the odor persists after the cleaning and exchanging the air filter, it's best to reach back out to a professional to diagnose and repair any hidden issues with your air conditioning. Or, the tech can tell you if your air conditioning ought to be replaced.

If you are wanting to upgrade, AZ Air Conditioning and Heating can help find the ideal unit to fit your home’s needs. We deliver trustworthy, expert air conditioner installation in Los Angeles.

Your AC Smells Like Chemicals

If the smell of chemicals is coming from your air conditioner, it could be caused by a refrigerant leak. In a situation where the refrigerant leaks, it can create a chemical scent that is often described as smelling like chemicals or paint thinner, vinegar or acetone.

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

If you think your system has a refrigerant leak or an electrical issue, it's important to shut down 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 prevent injury or damage to your house.

Strange Smell Coming from Your AC? Contact the Experts at AZ Air Conditioning and Heating

If your air conditioner reeks and you aren’t able to fix it easily on your own, reach out to the cooling specialists at AZ Air Conditioning and Heating. We have lots of experience working with a wide variety of air conditioning systems. Our crew has fixed a multitude of air conditioning troubles through the years—including funky smells. Call us today for quality AC repair in Los Angeles!