Why Does My AC Smell? A Portland Tech Answers

If you smell a terrible odor coming from your AC, unfortunately, there's likely an issue with your AC system that a professional will need to fix.

To diagnose the issue, you’ll need to know what kind of smell is coming from your AC. A few of the most common odors are:

• Musty/dirty socks
• Rotten eggs
• Chemicals

While it’s difficult to give the exact reason behind the smell without inspecting your AC, we can provide some general guidance about why you’re smelling these unpleasant odors.

Want a Portland NATE-certified technician to get rid of that smell? Contact Four Seasons to repair your AC.

You probably have a mold or mildew problem. Typically, mold or mildew occurs when your AC has a:

1. Clogged condensate line: When your AC cools your home, it does so by stripping heat and humidity from the indoor air. The moisture from the humidity then exits your home through a condensate drain line.

Usually, the moisture from your home’s AC collects in a drain pan and quickly exits your home via your condensate drain line. However, if the condensate line is clogged with dirt or debris, the moisture can back up in the drain line and sit in the drain pan.

The drain pan is located in a warm, dark place, so when water sits in the drain pan for a while, mold and mildew can start to grow.

Signs you may have a clogged condensate line include:

• Water pooling around your indoor unit
• Your AC running for a short period of time then shutting off

If you think you may have a clogged condensate drain line, you should call an HVAC technician. They will be able to take a look at your condensate drain line and clear it of any debris if there is a clog.

2. Dirty evaporator coil: As we mentioned above, your AC cools your home by stripping your home’s air of heat and humidity. The evaporator coil is the part of your AC that removes heat and humidity from your home’s air.

If the evaporator coil is dirty, the humidity can mix with the dirt on your coil, creating mold and that “dirty sock” smell.

If you think this is your issue, you’ll want to hire a professional to clean the evaporator coil. The evaporator coil is a delicate part of your AC that can be easily damaged, so coil cleaning is best left to a professional.

3. Leaky ductwork problem: Your ductwork typically lives in unconditioned areas of your home, like the attic, where mold and dust thrive.

If your ductwork has leaks, mold spores and dust mites can enter into your ductwork and grow, resulting in that “dirty sock” smell.

If you think you may have leaks in your ductwork, you’ll need to reach out to a professional. An HVAC tech can clean and seal your ductwork to get rid of the current mold and prevent future mold growth.

… You could have one of two problems:

• A dead animal in your ductwork: Unfortunately, it’s possible that there may be a critter stuck in your ductwork. Contact a professional to inspect your ductwork.
• A gas furnace leak: Since your furnace shares the same space as your AC, if there’s a gas leak, you will smell it around your AC as well. Contact a professional to inspect your furnace.

… You most likely have a refrigerant leak. Refrigerant is a chemical agent that removes heat from your home. When it’s exposed, it has a sweet chemical odor.

On top of the odor, when there’s a refrigerant leak, you might also notice signs like:

• Increased energy bills
• Hissing or bubbling sounds coming from your AC
• Warm air blowing from your AC vents

If you suspect that you have a refrigerant leak, you’ll want to contact an HVAC professional to come to inspect and seal it. Refrigerant is toxic so it’s best to let a technician handle the leak.

Our Portland technicians can repair any AC brand and model. On top of high-quality AC repairs, we also provide convenience with our 2-hour appointment slots and same-day service.