When your air conditioner starts spewing weird or gross odors, it is necessary to take notice because it could be a sign of a major problem. Dismissing unpleasant smells coming from your cooling system can lead to additional damage to your AC or even pose a risk to your health and safety.

Depending on the cause of the odor, the root of the problem might be bacteria or fungus in the system. Other times, it could also signal something mechanically wrong with the air conditioning system. Some smells are even indicative of an unsafe situation, including a natural gas leak.

At Retro HVAC Service & Installation, 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 qualified professionals has smelled it, too—and fixed it! We’ve earned the reputation as the first call for air conditioning repair in Philadelphia.

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

The Air Conditioning Smells Like Feet

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

Another potential reason for the stench of dirty feet may be a dirty air filter. If an air filter becomes filled with dirt, dust and other particles, it can cause poor air quality and a musty smell that it similar to the smell of feet.

To solve 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 change the air filter regularly to promote good air quality and prevent the formation of bacteria and fungus.

Your AC Smells Like Rotten Eggs

If your air conditioning unit reeks of 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 can be 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, evacuate the building and call your gas company or emergency services immediately.

Your AC Smells Like Mildew

If your AC emits a smell like mildew, it might be due to a accumulation of moisture inside the unit. When moisture collects inside a cooling system, it can cultivate the growth of mold and mildew. This can cause a musty odor that bears a resemblance to mildew.

Another possible reason 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 is similar to mildew.

Routine air conditioning maintenance from Retro HVAC Service & Installation can help prevent both of these situations, because a good cleaning, inspection and filter change is a very good way to keep your system working at its best!

The Air Conditioning Smells Like Urine

One of the most unpleasant scenarios is when the air coming out of your HVAC system smells like urine.

If your air conditioner smells like urine, it could could be caused by multiple 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 damp environment that favorable for bacterial growth. The bacteria can create a foul odor that some people describe as smelling like urine.

Another potential 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 choked with debris, it can cause water to back up and collect inside the unit. This can produce a musty smell that resembles urine.

Your AC Smells Like Burning Plastic

If your air conditioner smells like burning plastic, this could indicate an electrical issue with the unit. Over time, the electrical components in the air conditioning system can wear out or break, 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 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 air conditioner smells like gas, there could be a natural gas leak in the unit or in your home. Natural gas has a distinct odor, often described as smelling like rotten eggs or sulfur. That’s because this scent is added to natural gas to make it easily detectable.

As we said earlier, a natural gas leak can be VERY dangerous and requires 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.

My Air Conditioner 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 produces an environment that is conducive to the growth of bacteria and mold. This can cause a foul odor that can be 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 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 correct 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 proper steps to remove any contaminants and prevent the problem from recurring.

Your AC Smells Like Vinegar

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

To fix the issue, it's essential to have a skilled mechanic inspect and clean your air conditioning.  If the odor continues after the cleaning and exchanging 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, they can tell you if your air conditioning ought to be replaced.

If you are wanting to upgrade, Retro HVAC Service & Installation can help select the right unit to fit your home’s needs. We provide trustworthy, skilled air conditioner installation in Philadelphia.

The Air Conditioning Smells Like Chemicals

If the smell of chemicals is coming out of your air conditioning equipment, it could be caused by a refrigerant leak. If 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 cause of the smell could be a problem with the electrical wiring or components inside the air conditioning system. This can produce a burning smell that resembles chemicals or burning plastic.

If you suspect a refrigerant leak or an electrical concern, 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 prevent injury or damage to your residence.

A Nasty Odor Coming from the Air Conditioning? Call the Pros at Retro HVAC Service & Installation

If your air conditioner reeks and you aren’t able to fix it simply on your own, contact the cooling experts at Retro HVAC Service & Installation. We have lots of experience working with a wide variety of cooling systems. Our crew has fixed many air conditioning problems throughout the years—including strange smells. Call us today for quality AC repair in Philadelphia!