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

Depending on the smell, the culprit could be bacteria or fungus in the system. Other times, it could also signal something mechanically wrong with the air conditioning system. Some smells are a warning of a hazardous scenario, including a natural gas leak.

At Central Heating & Plumbing, we have a nose for these sorts of things. If you smell something weird coming from your air conditioner, chances are our team of qualified professionals has smelled it, too—and fixed it! We’ve earned our reputation as the first call for air conditioning repair in New Castle.

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

My Air Conditioner Smells Like Feet

If your air conditioner smells like feet, it may be caused by a buildup of bacteria or fungus in the unit. When moisture builds inside the unit, it can establish an environment that is beneficial to the growth of bacteria and fungus. This can produce a nasty odor that is often described as smelling like stinky feet.

Another potential explanation for the smell may be a dirty air filter. When the air filter becomes filled with dirt, dust and other contaminants, it can cause low air quality and a musty smell that bears a resemblance to feet.

To fix 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 exchange the air filter routinely to promote good air quality and restrict the growth of bacteria and fungus.

My Air Conditioner Smells Like Rotten Eggs

If your air conditioning unit smells like rotten eggs, it could be caused by 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, which is added to it to make it easily detectable.

A natural gas leak can be very 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 is giving off an odor like mildew, it might be due to a collection of moisture inside the unit. When moisture accumulates inside a cooling system, it can promote the growth of mold and mildew. This can cause a musty smell that resembles mildew.

Another possible cause of the smell could be a soiled air filter. When 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 Central Heating & Plumbing can help avoid both of these problems, because a good cleaning, inspection and filter change is a very good way to keep your system running at its best!

My Air Conditioner Smells Like Urine

One of the most undesirable scenarios is when an air conditioner smells like urine.

If your air conditioner smells like urine, it could be traced back to a number of things. One possible cause is a buildup of bacteria or mold in the your cooling system. This can happen in the event that moisture accumulates in the system and creates a damp environment that is conducive to bacterial growth. The bacteria can create a foul odor that resembles urine.

Another possible cause of the scent of urine 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 filled with debris, it can cause water to back up and build up inside the unit. This can create a musty smell that can stink like urine.

My Air Conditioner Smells Like Burning Plastic

If your air conditioner smells like burning plastic, this could indicate an electrical problem with the unit. After some time, the electrical components 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 stuck in the the air conditioner. If something foreign gets caught in the air conditioning system, it can become hot and cause a smell that reminds people of burning plastic.

If you think you smell burning plastic coming from your AC unit, it’s worthwhile to contact a professional right away.

My Air Conditioner 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 distinct smell, often described as smelling of rotten eggs or sulfur. That’s because this scent is added to natural gas so that it is easily detectable.

As stated previously, a natural gas leak can be VERY harmful 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, get everyone out of the building and contact your gas company or emergency services right away.

Why My Air Conditioner 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 potential cause of the smell could be a dead animal or other biological material caught inside the air conditioning system. This often is possible if an animal such as a mouse or bird becomes trapped inside the unit and dies.

To correct the issue, it's worthwhile to have a professional examine and clean your cooling system. They can identify 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 several reasons a home's air conditioner smells like vinegar. One possible cause of the smell could be a plugged air filter. A second possible cause of the smell could 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 important to have a skilled mechanic look at and clean your air conditioning.  If the odor continues after the cleaning and changing 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 ought to be replaced.

If you are looking to upgrade, Central Heating & Plumbing can help select the ideal unit to fit your home’s needs. We offer dependable, expert air conditioner installation in New Castle.

My Air Conditioner Smells Like Chemicals

If the smell of chemicals is coming from your air conditioning unit, it could be the result of a refrigerant leak. When the refrigerant leaks, it can create a chemical aroma that some people describe as smelling like chemicals or paint thinner, vinegar or acetone.

One other possible source of the smell could be something wrong with the electrical wiring or parts inside the air conditioning system. This can produce a burning smell that resembles chemicals or burning plastic.

If you suspect a refrigerant leak or an electrical problem, 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 avoid injury or damage to your home.

Strange Smell Coming from Your AC? Call the Pros at Central Heating & Plumbing

If your air conditioner reeks and you aren’t able to fix it smoothly on your own, reach out to the cooling professionals at Central Heating & Plumbing. We have lots of experience working with a wide variety of HVAC systems. Our crew has fixed many air conditioning troubles throughout the years—including weird smells. Call us today for quality AC repair in New Castle!