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

Depending on the cause of the odor, the root of the problem could be bacteria or fungus in the system. Other times, it could also sign something mechanically wrong with the AC. Some smells are a sign of an unsafe scenario, including a natural gas leak.

At Alpine Summit Heating & Cooling, we have a nose for these sorts of things. If you smell something peculiar coming from your air conditioner, there's a good chance our team of skilled professionals has smelled it, too—and fixed it! We’ve earned our reputation as the premier company for air conditioning repair in Athol.

What does a particular smell coming from your AC mean? Here are a few frequent air conditioner aromas and what they may mean:

My Air Conditioner Smells Like Feet

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

Another potential cause of the stench of dirty feet could be a dirty air filter. When the air filter becomes filled with dirt, dust and other debris, it can lead to substandard air quality and a musty smell that it similar to the smell of feet.

To correct this issue, it's important to have a professional 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 routinely to promote good air quality and restrict the formation of bacteria and fungus.

My Air Conditioner Smells Like Rotten Eggs

If your air conditioning equipment 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 recognizable 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 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, evacuate the building and call your gas company or emergency services right away.

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 forms inside an air conditioner, it can foster the growth of mold and mildew. This can cause a musty stench that resembles 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.

Regular air conditioning maintenance from Alpine Summit Heating & Cooling can help protect against both of these problems, because a good cleaning, inspection and filter change is a terrific way to keep your system operating at its best!

My Air Conditioner Smells Like Urine

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

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

Another feasible 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 correctly, but if the drain line becomes choked with debris, it can cause water to back up and accumulate inside the unit. This can generate a musty smell that resembles urine.

My Air Conditioner Smells Like Burning Plastic

If your air conditioner smells like burning plastic, this could indicate an electrical issue with the unit. After a while, the electrical elements in the air conditioning system can wear out or bust, which can create a burning smell that resembles plastic.

Another possible cause of the smell could be a foreign object stuck in the unit. If something foreign gets caught in the air conditioning system, it can get hot and cause a smell that reminds people of burning plastic.

If you notice something that smells like burning plastic coming from your AC unit, it’s essential to phone a professional right away.

My Air Conditioner Smells Like Gas

If your AC smells like gas, there could be a natural gas leak in the unit or in the surrounding area. Natural gas has a distinct odor, often described as smelling similar to rotten eggs or sulfur. That’s because a smell is incorporated into natural gas to make sure that it is 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, get everyone out of the building and contact your gas company or emergency services as soon as possible.

Why My Air Conditioner Smells Like Fish

Should 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 foul odor that is often described as smelling like fish or, as mentioned earlier, it also can cause a smell like dirty feet.

Another plausible explanation for the smell could be a dead animal or other biological material caught inside 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 fix the issue, it's worthwhile to have a professional check out and clean your HVAC 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 multiple reasons a home's air conditioner smells like vinegar. One possible cause might be a plugged air filter. Another possible cause of the smell might be a refrigerant leak. Sometimes after the refrigerant leaks, it can make a chemical odor that is described as smelling of vinegar.

To fix the issue, it's beneficial 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 identify and repair any underlying issues with your air conditioning. Or, they can tell you if your air conditioning ought to be replaced.

If you are looking to upgrade, Alpine Summit Heating & Cooling can help select the correct unit to fit your home’s needs. We deliver reliable, expert air conditioner installation in Athol.

My Air Conditioner Smells Like Chemicals

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

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

If you think your system has a refrigerant leak or an electrical issue, it's important to turn off your air conditioning system as soon as possible 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.

Strange Smell Coming from Your AC? Call the Pros at Alpine Summit 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 Alpine Summit Heating & Cooling. We have years of experience working with a wide variety of HVAC systems. Our crew has fixed a multitude of air conditioning concerns over the years—including weird smells. Call us today for quality AC repair in Athol!