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

Depending on what you're smelling, the cause may be bacteria or fungus in the system. In other cases, it could also sign something mechanically wrong with the air conditioner. Some smells are a warning of an unsafe problem, such as a natural gas leak.

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

What does a certain smell coming coming from your cooling system mean? Here are several typical air conditioner smells 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 unit. When moisture collects inside the unit, it can establish an environment that is beneficial to the spread of bacteria and fungus. This can result in a nasty odor that is often described as smelling like stinky feet.

Another likely explanation for the stench of dirty feet may be a dirty air filter. When the air filter becomes choked with dirt, dust and other debris, it can result in substandard air quality and a musty smell that it similar to the smell of feet.

To solve this issue, 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 on a regular basis to ensure good air quality and prevent the formation of bacteria and fungus.

My Air Conditioner Smells Like Rotten Eggs

If your air conditioning equipment stinks like rotten eggs, it might be the result of 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 very 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, get everyone out of the building and call your gas company or emergency services immediately.

My Air Conditioner Smells Like Mildew

If your cooling system emits a smell like mildew, it could 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 stench that bears a resemblance to mildew.

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

Routine air conditioning maintenance from Heartland Heating & Cooling can help prevent 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 undesirable things is when an air conditioner smells like urine.

If your air conditioner stinks like urine, it could be due to a variety of factors. One likely cause is a buildup of bacteria or mold in the your HVAC. This can happen in the event that moisture accumulates in the system and creates a moist environment that can promote bacterial growth. The bacteria can emit 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 build up inside the unit. This can create a musty smell that resembles urine.

The Air Conditioning Smells Like Burning Plastic

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

Another possible root cause of the smell could be a foreign object that somehow got in the HVAC system. If something foreign gets trapped in the air conditioning system, it can become hot and cause a smell like 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.

My Air Conditioner Smells Like Gas

If your air conditioning smells like gas, there could be a natural gas leak in the unit or in your home. Natural gas has a distinct aroma, often described as smelling similar to rotten eggs or sulfur. That’s because a smell is put into natural gas so that it is easily detectable.

As stated previously, a natural gas leak can be VERY dangerous and needs 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 contact your gas company or emergency services as soon as possible.

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 causes an environment that promotes the growth of bacteria and mold. This can cause a disgusting 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 trapped in the air conditioning system. This often can happen if an animal such as a mouse or bird is trapped inside the unit and dies.

To correct the issue, it's important to have a professional check out and clean your air conditioning system. They can 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 numerous reasons a home's air conditioner smells like vinegar. One possible cause might be a plugged air filter. One other potential cause of the smell may be a refrigerant leak. If the refrigerant leaks, it can generate a chemical odor that is described as smelling of vinegar.

To fix the issue, it's important to have a skilled tech examine and clean your air conditioning.  If the odor persists 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, the mechanic can tell you if your air conditioning needs to be replaced.

If you are looking to upgrade, Heartland Heating & Cooling can help locate the correct unit to fit your home’s needs. We offer reliable, expert air conditioner installation in Des Moines.

My Air Conditioner Smells Like Chemicals

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

One other possible reason for the smell could be a problem with the electrical wiring or hardware inside the air conditioning system. This can cause a burning smell that it similar to chemicals or burning plastic.

If you think your system has a refrigerant leak or an electrical concern, 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 prevent injury or damage to your house.

Strange Smell Coming from Your AC? Call the Pros at Heartland Heating & Cooling

If your air conditioner smells nasty and you aren’t able to fix it quickly on your own, reach out to the cooling specialists at Heartland Heating & Cooling. We have lots of experience working with a wide variety of AC systems. Our crew has fixed countless air conditioning troubles throughout the years—including weird smells. Call us today for quality AC repair in Des Moines!