Why Does My Air Conditioner Smell?

Suppose it’s a scorching day outside, and you happily make your way to the front door of your comfortable, air-conditioned home only to receive a nasty whiff of an unpleasant smell. After a quick investigation, you quickly discover that the odor is coming from your air conditioner. You can’t stand the heat, but you can’t stand the smell either. If you find yourself facing this scenario, you must identify the cause to determine the solution. Here are some common causes and solutions to a foul-smelling air conditioner.

Mold and Mildew

If your air conditioner comes into contact with excessive amounts of moisture, it could become a breeding ground for mold and mildew. These can grow in your unit and blow particles throughout your entire home. That will not only make your home smell, but it can also be dangerous for you and your family. Breathing air sullied with mold and mildew can lead to serious respiratory problems.

Mold and mildew have a distinct and unmistakable smell. If you notice this coming from your air conditioner, the equipment should be cleaned immediately. The problem may be localized in the filter, which can simply be replaced. However, the problem is likely to be more extensive and require professional assistance to clean the device and associated ductwork.

Refrigerant Leak

Refrigerant is the liquid in your air conditioning system that provides the cool air you enjoy so much in the summer. A leak can occur when something breaks down inside the unit. When there is a refrigerant leak, you may not get the same cold air you did before. The air may actually blow hot.

A refrigerant leak smells somewhat sweet but similar to chloroform. Turn off your AC and make an appointment with an experienced technician. If you’re on Long Island, one of our experts from B.A.C. Systems Inc. would be glad to help. Our technician will repair the leak and add more fluid to the unit.

Electrical Problems

Your air conditioner runs on electricity and contains numerous electrical components, such as:

  • Circuit boards
  • Compressors
  • Fans
  • Wiring

Problems occur when components break down and don’t work properly, causing friction. The electrical items can even literally burn and start a fire. This could lead to a completely ruined unit or even destroy your home.

Electrical problems smell as if something acrid is burning. That’s because it quite possibly is. Turn the unit off immediately. If you’ve caught the problem early enough, a technician might be able to replace the faulty component. Otherwise, it may be time to consider purchasing new equipment.


Cooling systems have some of their components outside. Occasionally, a critter can find an opening and make its way into the unit for relief from the heat. Unfortunately, these unwanted pests won’t find a safe home in your air conditioner, and they’re likely to die. If this happens, the smell of decay will permeate your house every time you turn on the AC. It will continue to grow worse until the problem is resolved. This can be done by simply having the nuisance removed. Hopefully, the intruder didn’t cause any further damage during its stay.

Gas Leak

The most serious smell on our list comes from a gas leak. Gas leaks usually occur when there is corrosion inside the system. Natural gas has no intrinsic odor, but the gas company adds one to it as an advance warning of a problem before it gets too bad. This is usually reminiscent of rotten eggs, and it should alert you to imminent danger. Turn off the gas supply to your home and call for emergency services immediately.


Smoking leads to bad skin, wrinkles, yellow teeth, and, of course, a pervasive odor. If you smoke in your home, the smoke will inevitably get into the air conditioner. Eventually, it will start to blow the smoke back out into the house, making everyone inhale it. Plus, the smell will seep into the walls and everyone’s clothes and hair. It doesn’t damage the unit so much as your beautiful home, and it’s horrible for young children. In this situation, you can clean the unit and make a choice to smoke outside for the good of everyone in your household. However, it shouldn’t require repair or replacement.

If your air conditioner isn’t smelling as it should, then reach out to us at B.A.C. Systems Inc. today for a consultation and service anywhere in Farmingdale or on Long Island. We perform a complete range of cooling and heating repair, installation, and maintenance. You can also rely on us for your roofing and masonry needs. Besides that, we install siding, windows, and gutters. Call us today to schedule an appointment.

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