Why Does My AC Smell Bad? Common Smells & How to Fix Them

You go to turn on your air conditioner on a hot day and you are met by a horrible stench from the air registers. What is that smell!? And how can you get rid of it fast?

Here are common smells that you might notice coming from your AC and how you can fix them to restore balance in your home from our team at Super Heat & Air. Let’s go! 

Common Air Conditioner Smells and Solutions

Here are some common smells that you may notice coming from your air conditioner and what you can do about them.

Rotten Eggs or Sulfur

Be warned. If you smell rotten eggs or sulfur coming from your air conditioning, it almost always means one thing: there is a gas leak in your home that is getting circulated through your ductwork.

Natural gas is a hazardous substance. It can catch fire, explode, and cause severe and often fatal issues in the human bloodstream.

How to Fix: Turn off the gas supply to your home if you can do so safely. Have everyone leave the house and call 911 or your gas company to report the leak. Don’t go back into the house until the leak has been fixed and the house has been aired out.

Dirty Socks

If your home smells like a locker room and the funky smell is emanating from the air registers, there may be standing water and bacteria growth in your air conditioner. As foul as this may smell, it is usually not harmful to your health.

How to Fix: First, change your air filter if you haven’t in a while. Next, call our team at Super Heat & Air to clean and disinfect your AC system, especially the drain line and evaporator coil. Ideally, you should schedule HVAC maintenance with our team every year.


If you notice a faint burning smell when you first turn your HVAC on for the season, it is usually nothing serious. But be warned, a strong burnt or gunpowder smell can indicate an electrical fire hazard such as a short circuit, overheating, or frayed wiring that is causing a spark.

How to Fix: Wait a couple of minutes to see whether the smell dissipates and was just a faint odor. For a more pungent odor, turn the system off, have everyone evaluate the home, and call the fire department. Once the fire department checks for fire hazards, contact our team at Super Heat & Air to repair or replace your air conditioner.

Exhaust Fumes

Your AC should not smell like exhaust

Cigarette Smoke

If you have a family member who frequently smokes indoors, the stale smoke will be absorbed by your HVAC filter and then cycled throughout your home.

How to Fix: Make a habit out of changing your air filter every 30 days and have the ducts cleaned by an expert at least once a year. And maybe talk to your family member about quitting smoking…


If your kitchen garbage can isn’t the culprit for a garbage-like odor in your home, it could mean that a rodent, bird, or critter has died in your ductwork. Running your air conditioner is spreading the smell throughout your home.

How to Fix: You will need to hire a professional to remove the animal’s remains from your home and clean your duct system. Until then, turn off the air conditioner to limit the spread of the smell and open your windows for some fresh air. 

Keep Your Air Clean & Safe

If you notice any of the above smells or any other problems with your HVAC system, don’t wait, call our Superfast team at Super Heat & Air! Our AC pros will clean, repair, or replace your air conditioning system so you can breathe better!

Skip to content