Skip to content

What's Behind The Smell?

The SquareGuy Oct 21, 2021 11:09:08 PM


Given that your air conditioning system plays such an integral role in your home’s comfort and energy efficiency, you should always be on the lookout for signs that may indicate a serious problem. By dealing with potential issues promptly, you can prevent AC downtimes and ensure your home is prepped and ready for the warmer months ahead. But how exactly do you determine if your air conditioner is the issue? Easy–your nose will know.


Depending on the model, air conditioners may operate with a little noise–but they generally shouldn’t give off an unusual odor. If your inside unit smells  funny every time you switch it on, this can only mean the system has developed a problem. 

Decoding Different AC Smells

Your air conditioner may produce different odors depending on the underlying issue. Whatever it is, however, it can’t be good news. Here’s a quick rundown:

  • The Smell of Musty, Dirty Socks. 
    An AC that generates a smell like a gym locker room may take away from your enjoyment of a cool, comfortable home. Dirty evaporator coils, which can develop mold and other growth buildup due to condensation, are a common reason for this odor.  

What to Do. You just need to turn to a reliable technician who can clean your evaporator coils and unclog the drain pans to prevent mold growth and the musty, dirty-sock smell associated with it. Changing your air filter regularly will also help.

  • A Distinctive Chemical Smell. It’s never a good sign when your AC starts smelling like chemicals when you turn it on. This can mean the system has a refrigerant leak–a serious issue that can lead to premature air conditioner failure and replacement if overlooked. In addition to the chemical odor, there are other signs that may point to a refrigerant leak. These include bubbling and hissing sounds when the system is running, inconsistent indoor temperatures, warm air blowing from the vents and ice buildup on refrigerant lines or the evaporator coil is a sure sign of trouble.

What to Do. Call your local HVAC company immediately. If the leak is caught early enough, it may only require some quick repairs to fix the leak, after which the HVAC technician will recharge your AC with the right amount of refrigerant. If the leak is severe and the system is already compromised, your best bet is a replacement.

  • A Vinegar-Like Smell. There are several possible reasons for a sharp, acidic smell coming from your indoor unit. The air filter or condensate pan may be clogged, or the ductwork could have mold buildup. Excess condensation is another possible cause.

What to Do. Replacing the air filter may help. but if it doesn’t get rid of the smell, you may have to call your HVAC technician. 

  • A Burning Smell. This may be due to a broken capacitor that’s causing the motor to overheat, or perhaps a broken fan belt or loose electrical connections and is never good. A number of things can go wrong if you ignore the burning smell coming from your air conditioning system–the worst of which is a fire–so have it checked immediately. What to Do. Again, the best idea is to have your system checked promptly by a trusted HVAC company. They’ll know what to do and will observe the necessary safety precautions to ensure the system is fixed in an efficient manner.

Leave a Comment