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Top Air Conditioner Smells & What They Mean

Top Air Conditioner Smells & What They Mean

If your air conditioner smells bad when you turn it on, it’s time to take a closer look. Foul odors coming from your AC unit could indicate an underlying problem that needs a professional’s attention. Don’t put your safety and comfort at risk. Keep reading to see what causes these smells and how an IERNA’s technician can eliminate them.

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What Causes Air Conditioners to Smell Bad?

Not sure why your air conditioner has a funky smell? Here are some possible reasons.

Excess Condensation

As warm air from outside passes over the cooling coils in your AC system, condensation forms. While a regular amount of moisture won’t cause problems, excess condensation can cause mold to grow, and we all know mold smells musty.

Clogged Air Filter

Your AC unit’s air filter captures airborne contaminants before they get a chance to enter your fresh air supply. Over time, these contaminants accumulate, causing the filter to clog. A clogged air filter might start to smell like mold or fungus.

Full or Clogged Condensation Pan

The condensation pan collects moisture that drips from the cooling coils as they cool down warm outside air for indoor use. Accumulated moisture might produce a musty smell.

8 Most Common AC Smells to Look Out For

You know what causes air conditioners to smell bad, but what about the kind of smells they produce when something goes wrong? Brush up on the eight most common air conditioner odors fellow Florida residents deal with.

Burning Smell

If the circuit board, wires, fan, or compressor malfunctions, they can spark and cause a small internal fire. Only a licensed professional should address this problem.

Another reason your AC might produce a burning smell is burning dust. When your air conditioner isn’t being used, like during the winter, dust accumulates on its components. When you turn on the unit for the first time in the spring, that dust burns off and may emit an unpleasant odor. But don’t be alarmed by this.

Rotten Eggs or Vinegar

When airborne contaminants build up on the air filter, they can make your air conditioner smell like rotten eggs or vinegar. That’s because mold and bacteria begin to form. When air blows past the mold and bacteria, it can carry that unpleasant smell right along with it.


When condensation builds up inside your unit or the air filter gets clogged, a musty smell might emerge. This odor is not only unpleasant to smell but threatens your indoor air quality.

Car Exhaust

Your air conditioner may not be gas powered, but it can still produce a car exhaust smell. But how does this happen? Fluids can leak from the unit, creating an odor resembling exhaust fumes.


If your system smells like chemicals, it may be overheating. It could also simply be burning dust on the heat exchanger.


A fan motor or circuit board that short circuits can create sparks that smell like something is burning. It might even emit a gunpowder-like odor. If you notice this smell, call us immediately for emergency repairs.


Your air conditioner constantly recycles air in and out of the unit. If anyone in your household or workplace smokes, the cigarette smell will never leave. Cigarette smoke can cause everything from headaches to asthma attacks, so it’s important to fix the problem quickly.

Dirty Socks

No one likes the smell of dirty socks. That’s why we peel them off our feet and throw them right into the laundry hamper at the end of the day. What if your entire house or office smelled like dirty socks? Bacterial growth that accumulates in the air filter can start to smell like dirty socks.

Why You Should Call a Professional to Inspect Your AC Unit

While some AC repairs are easy to DIY, others require the expertise of an HVAC technician. If your air conditioner starts to smell funny every time you use it, here’s how we can help:

Routine Maintenance: A well-maintained air conditioner is a healthy air conditioner. Our team will replace the air filter, clean internal components, dust off the exterior, and much more, giving you more time to do what you enjoy. Routine maintenance will enhance the efficiency and maximize the longevity of your AC unit.

Repairs: Sometimes, your air conditioner needs more than maintenance. If a component keeps malfunctioning or sustains minor damages, we’ll perform the necessary repairs to get it up and running again. That way you can save time and money on a unit replacement.

Ierna’s is The One-Stop AC Shop

Whether you need to schedule an AC tune-up, repair, or installation, IERNA’s is the name you can trust to do the job right. We deliver top-notch HVAC services at affordable rates to help you achieve your comfort goals without breaking the bank. Follow the link below to schedule the service you need with our convenient online booking.

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