If Your Air Conditioner Smells, Here's How to Fix It

When your air conditioner starts emitting strange or funky aromas, it is necessary to take notice because it could be a sign of a significant problem. Ignoring unpleasant smells coming from your cooling system may lead to further damage to your HVAC system or even pose a risk to your health and safety.

Depending on what you’re smelling, the root of the problem may be bacteria or fungus in the system. On the other hand, it could also indicate something mechanically wrong with the air conditioning system. Some smells are a warning of a dangerous scenario, including a natural gas leak.

At B & B Heating & Cooling, we have a nose for these sorts of things. If you smell something peculiar coming from your cooling system, you can bet that our team of qualified professionals has smelled it, too—and fixed it! We’ve earned a reputation as the premier company for air conditioning repair in Florissant and St. Charles.

What does a certain smell billowing coming from your AC mean? Here are several common air conditioner smells and what they might mean:

My Air Conditioner Smells Like Feet

If your air conditioner smells like feet, it could be because of a buildup of bacteria or fungus in the system. When moisture builds inside the unit, it can create an environment that is favorable to the development of bacteria and fungus. This can cause a foul odor that is often described as smelling like feet.

Another likely cause of an odor of stinky feet may be a dirty air filter. When the air filter becomes choked with dirt, dust and other contaminants, it can result in substandard air quality and a musty smell that resembles feet.

To fix this dilemma, 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 replace the air filter on a regular basis to provide good air quality and restrict the formation of bacteria and fungus.

Your AC Smells Like Rotten Eggs

If your stinks like rotten eggs, it could be the result of 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 because of a substance 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 allow gas to escape 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 AC emits a smell like mildew, it may be due to a collection of moisture inside the unit. When moisture forms 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 explanation for the smell might be a dirty air filter. If the air filter becomes clogged, it can cause poor air quality and a musty smell that resembles mildew.

Annual air conditioning maintenance from B & B Heating & Cooling 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!

My Air Conditioner Smells Like Urine

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

If your air conditioning reeks of urine, it could be due to a variety of factors. One possible cause is a collection of bacteria or mold in the your HVAC. This can happen when moisture accumulates in the system and creates a wet environment that can promote bacterial growth. The bacteria can emit a foul odor that it similar to urine.

Another possible cause of the stink could be a blocked 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 collect inside the unit. This can create a musty smell that resembles urine.

The Air Conditioning Smells Like Burning Plastic

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

Another possible reason for the smell could be a foreign object lodged in the unit. If something foreign gets caught in the air conditioning system, it can get hot and emit a smell like burning plastic.

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

Your AC Smells Like Gas

If your AC smells like gas, it could be due to a natural gas leak in the unit or in another part of your home. Natural gas has a distinct aroma, often described as smelling of rotten eggs or sulfur. That’s because a smell is put into natural gas to make it easily detectable.

As stated before, a natural gas leak can be VERY harmful and requires immediate attention. If you suspect a gas leak, turn off your air conditioning system, open windows and doors to air out the home, leave the building and phone your gas company or emergency services straight away.

Why My Air Conditioner Smells Like Fish

If your AC smell like fish, this could be a sign of a build-up of bacteria or mold in the unit. Moisture causes an environment that is conducive to the growth of bacteria and mold. This can cause a strong odor that is sometimes described as smelling like fish or, as mentioned earlier, it also can result in a smell like dirty feet.

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

To solve the issue, it’s often necessary to have a professional inspect and clean your HVAC system. They can determine the source of the smell and take the correct steps to remove any contaminants and stop 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 clogged air filter. One other likely cause of the smell might be a refrigerant leak. If the refrigerant leaks, it can generate a chemical odor that resembles vinegar.

To fix the issue, it’s beneficial to have a skilled tech inspect 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 persistent issues with your air conditioning. Or, the mechanic can tell you if your air conditioning ought to be replaced.

If you are planning to upgrade, B & B Heating & Cooling can help select the ideal unit to fit your home’s needs. We provide trustworthy, skilled air conditioner installation in Florissant and St. Charles.

My Air Conditioner Smells Like Chemicals

If the smell of chemicals is coming out of your air conditioning unit, it could be caused by 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.

An additional possible source of the smell could be something wrong with the electrical wiring or hardware inside the air conditioning system. This can produce a burning smell that it similar to chemicals or burning plastic.

If you believe there is a refrigerant leak or an electrical concern, 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 dangerous and may require immediate attention to avoid injury or damage to your home.

A Nasty Odor Coming from Your Cooling? Call the Pros at B & B Heating & Cooling

If your air conditioner stinks and you aren’t able to fix it simply on your own, contact the cooling experts at B & B Heating & Cooling. We have plenty of experience working with a wide variety of air conditioning systems. Our crew has fixed many air conditioning concerns over the years—including weird smells. Call us today for quality AC repair in Florissant and St. Charles!