Smells Coming From Your AC System And What They Mean

When you start to notice that there are some weird smells being blown out from your home's HVAC system in conjunction with the cold air, then you have a problem somewhere. Depending on the odor that you are smelling, you could be dealing with anything from ice buildup to a fan motor overheating. Prior to contacting an HVAC contractor, though, it is a good idea to be familiar with the different types of odors that you may smell from your air conditioning unit and what they could mean. Keep reading to learn more.


When you smell a mildew odor coming from your home's HVAC system, it is likely indicative of the unit being unable to drain excess moisture properly. As your air conditioning system works to cool the home, it will also work to remove moisture from the interior air, and as that moisture builds up, it will begin to release a very unpleasant smell. Routine maintenance like replacing the AC filter can help, but if the mildew odor lingers, you will need to schedule an appointment with an HVAC contractor.


If you are smelling a burning odor that is similar to gunpowder, then you may be dealing with a short circuit or a faulty fan motor. If this type of issue is not addressed sooner rather than later, you can expect your system to stop working efficiently and possibly even fail on you completely.

Dirty Socks

The dirty sock smell is most common during the summer months of the year. This odor occurs when ice begins to build up on the unit due to frequent use. The wet area from the ice melting contributes to bacteria and mold growth on the coils, which is where the dirty sock odor comes in.

Exhaust Fumes

The motor in an HVAC system has fluid in it that is meant to keep the unit running efficiently. When these fluids begin to leak out of the unit, they will smell similar to the exhaust fumes that are generated by automobiles. This type of issue needs to be addressed quickly and before the HVAC system breaks down and needs to undergo a full replacement.

If you are smelling weird odors coming from your residential HVAC system, it is imperative that you get in touch with a professional air conditioning service in your local area to schedule an inspection and potential repair or replacement. Look for a residential AC professional to learn more.