When your air conditioner starts putting out unusual or gross odors, it is necessary to take notice because it could be a sign of a major problem. Ignoring unpleasant smells coming from your air conditioner can lead to additional damage to your HVAC system or even pose a risk to your health and safety.

Depending on the smell, the cause might be bacteria or fungus in the system. Other times, it could also sign something mechanically wrong with the air conditioning system. Some smells are even indicative of a harmful problem, like a natural gas leak.

At B & G HVAC, we have a nose for these sorts of things. If you smell something weird coming from your air conditioner, there's a good chance our team of talented pros has smelled it, too—and fixed it! We’ve earned our reputation as the premier company for air conditioning repair in Marshalltown.

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

The Air Conditioning 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 collects inside the unit, it can produce an environment that is beneficial to the development of bacteria and fungus. This can cause a foul odor that is often described as smelling like dirty feet.

Another possible reason for the stench of dirty feet may be a dirty air filter. If an air filter becomes clogged with dirt, dust and other debris, it can cause poor air quality and a musty smell that bears a resemblance to feet.

To solve this unpleasant situation, it's important to have a quality service tech inspect and clean your air conditioning system, including the evaporator coil, drain pan and condensate drain line. It's also important to replace the air filter regularly to provide good air quality and restrict the development of bacteria and fungus.

My Air Conditioner Smells Like Rotten Eggs

If your air conditioning unit reeks of rotten eggs, it may be caused by 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, which is because of a substance 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 allow gas to escape the area, make everyone leave the building and call your gas company or emergency services immediately.

My Air Conditioner Smells Like Mildew

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

Another possible cause of the smell may be a clogged air filter. If the air filter becomes clogged, it can lead to poor air quality and a musty smell that has a resemblance to mildew.

Regular air conditioning maintenance from B & G HVAC can help protect against both of these issues, because a good cleaning, inspection and filter change is a terrific way to keep your system running at its best!

The Air Conditioning Smells Like Urine

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

If your air conditioner stinks like urine, it could be due to a variety of factors. One likely cause is a collection 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 favorable for bacterial growth. The bacteria can create a foul odor that it similar to urine.

Another potential cause of the smell could be a clogged 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 accumulate inside the unit. This can generate a musty smell that is sometimes described as smelling of urine.

Your AC Smells Like Burning Plastic

If your air conditioning system smells like burning plastic, a possible cause could be an electrical problem with the unit. After a while, the electrical components 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 that somehow got in the unit. If something foreign gets trapped in the air conditioning system, it can become hot and emit 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.

Your AC 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 distinctive odor, often described as smelling similar to rotten eggs or sulfur. That’s because a smell is incorporated into natural gas so that it is easily detectable.

As stated 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, get everyone out of the building and phone your gas company or emergency services right away.

My Air Conditioner Smells Like Fish

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

Another plausible explanation for the smell could be a dead animal or other biological material trapped within the air conditioning system. This often can take place 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 check out and clean your cooling system. They should be able to 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 several reasons your air conditioning system smells like vinegar. One possible cause is a dirty air filter. Another likely cause of the smell may be a refrigerant leak. Sometimes after the refrigerant leaks, it can make a chemical odor that is similar to vinegar.

To fix the issue, it's beneficial to have a skilled tech examine and clean your air conditioning.  If the odor persists after the cleaning and changing of 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 tech can tell you if your air conditioning should be replaced.

If you are planning to upgrade, B & G HVAC can help locate the correct unit to fit your home’s needs. We offer dependable, professional air conditioner installation in Marshalltown.

My Air Conditioner Smells Like Chemicals

If the smell of chemicals is emitting out of your air conditioner, it could be due to a refrigerant leak. When the refrigerant leaks, it can create a chemical odor that people sometimes describe as smelling like chemicals or paint thinner, vinegar or acetone.

One other possible source of the smell could be problems with the electrical wiring or components inside the air conditioning system. This can cause 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 house.

A Nasty Odor Coming from the Air Conditioning? Call the Pros at B & G HVAC

If your air conditioner stinks and you aren’t able to fix it easily on your own, call the cooling specialists at B & G HVAC. We have years of experience working with a wide variety of cooling systems. Our crew has fixed countless air conditioning concerns throughout the years—including strange smells. Call us today for quality AC repair in Marshalltown!