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

When your air conditioner starts emitting weird or unappealing odors, it is a good idea to take notice because it could be a sign of a major problem. Dismissing unpleasant smells coming from your cooling system may 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 culprit could be bacteria or fungus in the system. Other times, it could also indicate something mechanically wrong with the AC. Some smells are a sign of an unsafe scenario, such as a natural gas leak.

At B & B Heating & Cooling, we are experienced at getting to the root cause of stinky smells. If you smell something peculiar coming from your AC, there's a good chance our team of skilled 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 particular smell billowing out of your air conditioning mean? Here are several common air conditioner aromas and what they could mean:

My Air Conditioner Smells Like Feet

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

Another likely reason for the smell could be a dirty air filter. When the air filter becomes choked 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 solve this problem, 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 protect against the growth of bacteria and fungus.

Your AC Smells Like Rotten Eggs

If your stinks like rotten eggs, it may 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 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, get everyone out of the building and call your gas company or emergency services immediately.

My Air Conditioner Smells Like Mildew

If your air conditioner smells like mildew, it may be due to a accumulation of moisture inside the unit. When moisture accumulates inside an air conditioner, it can cultivate the growth of mold and mildew. This can cause a musty odor that it similar to mildew.

Another possible reason for the smell could be a clogged air filter. When the air filter becomes clogged, it can lead to poor air quality and a musty smell that is similar to mildew.

Regular air conditioning maintenance from B & B Heating & Cooling can help prevent both of these issues, 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 your AC smells like urine.

If your air conditioning equipment stinks like urine, it could be traced back to a number of things. One likely cause is a accumulation of bacteria or mold in the air conditioning system. This can happen if moisture accumulates in the system and creates a wet environment that favorable for bacterial growth. The bacteria can emit a foul odor that is like urine.

Another potential cause of the scent of urine could be a blocked drain line. The condensation that forms inside the air conditioning unit needs to drain away effectively, but if the drain line becomes clogged 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 conditioning unit smells like burning plastic, a possible cause could be an electrical problem with the unit. After a while, the electrical parts in the air conditioning system can wear out or break, which can create a burning smell that resembles plastic.

Another possible reason for the smell could be a foreign object lodged in the HVAC system. If something foreign gets caught in the air conditioning system, it can become hot and emit a smell that reminds people of burning plastic.

If you notice something that smells like burning plastic coming from your air conditioner, it’s important to contact a professional right away.

The Air Conditioning Smells Like Gas

If your air conditioner 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 aroma, often described as smelling like rotten eggs or sulfur. That’s because a smell is incorporated into natural gas to make sure that it is easily detectable.

As mentioned previously, a natural gas leak can be VERY hazardous and needs immediate attention. If you suspect a gas leak, turn off your air conditioning system, open windows and doors to air out the home, evacuate the building and call your gas company or emergency services as soon as possible.

My Air Conditioner Smells Like Fish

If your air conditioner smell like fish, this could be a sign of 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 disgusting odor that is sometimes described as smelling like fish or, as mentioned earlier, it also can create a smell like dirty feet.

Another possible cause of the smell could be a dead animal or other biological material stuck in the air conditioning system. This often can take place if an animal such as a mouse or bird is trapped inside the unit and dies.

To solve the issue, it's worthwhile to have a professional inspect and clean your cooling system. They should be able to find the source of the smell and take the appropriate steps to remove any contaminants and prevent the problem from recurring.

My Air Conditioner Smells Like Vinegar

There could be multiple reasons an air conditioning system smells like vinegar. One possible cause might be a clogged air filter. Another likely cause of the smell could be a refrigerant leak. If the refrigerant leaks, it can make a chemical odor that is similar to vinegar.

To fix the issue, it's essential to have a skilled specialist examine and clean your air conditioning.  If the odor continues after the cleaning and replacing 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, they can tell you if your air conditioning needs to be replaced.

If you are planning to upgrade, B & B Heating & Cooling can help find the correct unit to fit your home’s needs. We offer reliable, expert 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. If the refrigerant leaks, it can create a chemical scent that is often described as smelling like chemicals or paint thinner, vinegar or acetone.

Another possible reason for the smell could be problems with the electrical wiring or hardware inside the air conditioning system. This can produce a burning smell that resembles chemicals or burning plastic.

If you believe there is a refrigerant leak or an electrical issue, 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 hazardous and may require immediate attention to avoid injury or damage to your house.

Weird Smells Coming from Your AC? Contact the Experts at B & B Heating & Cooling

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