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

Depending on the smell, the culprit might be bacteria or fungus in the system. In other cases, it could also indicate something mechanically wrong with the air conditioner. Some smells are a warning of a dangerous problem, including a natural gas leak.

At Northglenn Heating & Air Conditioning, we have a nose for these sorts of things. If you smell something weird coming from your cooling system, you can bet that our team of skilled specialists has smelled it, too—and fixed it! We’ve earned the reputation as the go-to team for air conditioning repair in Northglenn.

What does a specific odor billowing coming from your cooling system mean? Here are several frequent air conditioner aromas and what they may mean:

The Air Conditioning Smells Like Feet

If your air conditioner smells like feet, it can be caused by a buildup of bacteria or fungus in the system. When moisture accumulates inside the unit, it can produce an environment that is conducive to the development of bacteria and fungus. This can result in a bad odor that is often described as smelling like dirty feet.

Another potential explanation for the stench of dirty feet could be a dirty air filter. When your HVAC system's air filter becomes choked with dirt, dust and other particles, it can lead to substandard air quality and a musty smell that it similar to the smell of feet.

To solve this dilemma, 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 on a regular basis to ensure good air quality and restrict the growth of bacteria and fungus.

The Air Conditioning Smells Like Rotten Eggs

If your air conditioner reeks of rotten eggs, it might 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, that is 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, get everyone out of the building and call your gas company or emergency services right away.

Your AC Smells Like Mildew

If your air conditioner smells like mildew, it may be due to a collection of moisture inside the unit. When moisture accumulates inside the air conditioning system, it can promote the growth of mold and mildew. This can cause a musty smell that it similar to mildew.

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

Annual air conditioning maintenance from Northglenn Heating & Air Conditioning can help avoid both of these issues, because a good cleaning, inspection and filter change is a great way to keep your system working at its best!

Your AC Smells Like Urine

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

If your air conditioning equipment smells like urine, it could be traced back to a number of things. 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 damp environment that can promote 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 correctly, but if the drain line becomes clogged 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.

My Air Conditioner Smells Like Burning Plastic

If your AC smells like burning plastic, it might be because of an electrical problem with the unit. Over time, the electrical parts in the air conditioning system can wear out or break, which can produce a burning smell that resembles plastic.

Another possible reason for the smell could be a foreign object stuck in the the air conditioner. If something foreign gets stuck in the air conditioning system, it can become hot and emit a smell similar to burning plastic.

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

The Air Conditioning Smells Like Gas

If your AC 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 of rotten eggs or sulfur. That’s because an odor is incorporated into natural gas to make it easily detectable.

As stated earlier, a natural gas leak can be VERY dangerous and calls for immediate attention. When you suspect a gas leak, turn off your air conditioning system, open windows and doors to air out the home, leave the building and contact your gas company or emergency services straight away.

The Air Conditioning Smells Like Fish

If your air conditioning equipment 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 can be described as smelling like fish or, as mentioned earlier, it also can result in a smell like dirty feet.

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

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

Why My Air Conditioner Smells Like Vinegar

There could be several reasons an air conditioner smells like vinegar. One possible cause might be a plugged air filter. One other possible cause of the smell could be a refrigerant leak. When the refrigerant leaks, it can create a chemical odor that is described as smelling of vinegar.

To fix the issue, it's essential to have a skilled tech 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 find and repair any persistent issues with your air conditioning. Or, the tech can tell you if your air conditioning needs to be replaced.

If you are wanting to upgrade, Northglenn Heating & Air Conditioning can help find the correct unit to fit your home’s needs. We offer reliable, skilled air conditioner installation in Northglenn.

My Air Conditioner Smells Like Chemicals

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

Another possible source of the smell could be a problem with the electrical wiring or hardware inside the air conditioning system. This can result in a burning smell that it similar to 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 residence.

Weird Smells Coming from Your AC? Contact the Experts at Northglenn Heating & Air Conditioning

If your air conditioner smells nasty and you aren’t able to fix it easily on your own, contact the cooling professionals at Northglenn Heating & Air Conditioning. We have plenty of experience working with a wide variety of air conditioning systems. Our crew has fixed a multitude of air conditioning problems throughout the years—including strange smells. Call us today for quality AC repair in Northglenn!