If you are reading this, it is quite likely that you have had the unfortunate experience of noticing a less-than-favorable odor coming from your air conditioner. While an unusual smell can indicate that there is something amiss with your unit, it is an issue that is commonly experienced.

Depending on the culprit, it may be easy to resolve. The air that we breathe in has a direct impact on our health.

If you find that a bad smell is coming from your air conditioner, it should not be ignored. It is important to get it resolved as quickly as possible – not just for your comfort, but also for your health.

air conditioner in apartment

What Causes Bad Smells in an Air Conditioner?

There are numerous reasons why an air conditioner may develop an unpleasant smell. The culprit depends on the type of system that you are operating and the smell that is being emitted from that system. In most instances, the smell that you notice will determine what the issue is with the air conditioner. For that reason, we will outline the various smells and each will be followed with a potential culprit below:

  1. Fire – If you smell an odor like fire or something is burning, this is one of the more serious issues. Regardless of what type of air conditioner that you have, there are many wires, fans, there will be at least one circuit board, and even a compressor present. If you smell burning, it probably means that something IS burning or melting. If you have just turned your unit on after a long period of it being off, it could just be dust and the smell will quickly go away. If it is not going away, turn it off immediately and contact a HVAC professional. If you see actual smoke, call 911 immediately.
  2. Vehicle Exhaust – If you find that the odor you smell is similar to that of an exhaust from a vehicle, there’s an issue. There is no internal combustion-based engine within an air conditioner. There are liquids that are part of an AC unit, though. If these become heated, they are capable of putting off a smell that is similar to a car exhaust. In this instance, the culprit is likely a leak that has developed within the refrigerant line. What you may be smelling is freon. This smells like the coolant within a vehicle, but more on the sweet side. You should turn off the AC, open windows for ventilation, and call a HVAC professional immediately.
  3. Gas or Skunk-Like Odor – If you have an air conditioner that runs on natural gas and smell gas or you there’s an odor coming from the system that is similar to the smell that a skunk puts out, you may be facing a serious issue. You should turn off the gas line running into the AC, the line running into the home, and contact your gas company or a HVAC professional. As an added measure for your safety, you should open windows and ensure that the home is properly ventilated. If the odor is very strong, get everyone out of the home, cover any fish tanks you have in the home, and get all pets outdoors.
  4. Rotten Eggs – If you smell what resembles rotten eggs, you may have pests that have become stuck in the air conditioner or the ductwork associated with your air conditioner in your home. Examples include rodents, birds, lizards, and even insects. In most instances, a HVAC professional will be able to open up the system, identify the location of the issue, and resolve it rapidly. If something became lodged in your ductwork, the HVAC professional will evaluate the ductwork to see if there are any rips and tears. In some cases, ductwork can be easily repaired. In other cases – depending on the severity of the issue – you may have to have your ductwork completely replaced.
  5. Cigarette Smoke – If you – or anyone else – has ever smoked inside of the home where you reside, eventually, you may notice a cigarette smell being emitted from the unit. The evaporator coil in the unit and the filter will typically absorb this type of odor; however, if particles have become embedded in the system, once it is fired up, it will knock these particles loose and will result in them being pushed through the system. To correct this issue, the AC should be cleaned on a regular basis and you should place a new filter in the unit at least once every one to two months. Remember, always encourage people to smoke outdoors. Smoking indoors may cause many issues and may result in the malfunctioning of several systems – including your HVAC system.
  6. Mold or Musty – If the odor coming out of your air conditioner is stale and musty, you could have too much water within the drain pan of the system or in the drip lines. In turn, this moisture could result in the eventual growth of mildew or fungus. If you live in an area that is hot and experiences high levels of humidity, the issue could be moisture that has accumulated within the filters of the air conditioner. In this case, the lines and all of the ducts will need to be professionally cleaned. Do not be surprised if the HVAC technician discovers a leak while cleaning the unit. If this happens, that leak will need to be resolved for the continued safe operation of the air conditioner. Depending on the leak, this could be minimal – in terms of cost. It all depends on what is leaking and how severe the leak is to determine the overall cost for the repair.
  7. Chemical Smell – If you notice a type of chemical smell coming from your air conditioner, there are many potential culprits. First, it could be a leak of the refrigerant of the unit. Additionally, it could be that the evaporator coil is dirty or the condensate drain line has become clogged. Then, it could be something as simple as an open container of some type of chemical near the air handler that is located indoors. If you are unable to discover the reason for the smell, contact a HVAC professional immediately for assistance.

How Do I Prevent Bad Smells in My AC?

In order to prevent bad smells from developing in your air conditioner, you should ensure that you stay on top of the maintenance associated with the unit. You may set up a regular scheduled maintenance schedule with a HVAC professional. In addition to this, you may take several steps on your own. These include the following:

  • Clean or Replace AC Filters Prior to the Season of Operation
  • Schedule a Maintenance Checkup at Least Once a Year with a HVAC Technician
  • Deep Clean the Unit Once a Year
  • Have a Mold Guard Installed on the System
  • Utilize Self-Cleaning Technologies Like FrontWash

Contact Us

We here at Reynolds specialize in HVAC maintenance and repair. If you are noticing a bad odor coming from your air conditioner, contact us today for assistance. We will do a complete inspection of your system to determine the underlying cause.

Once the culprit is discovered, we will start the necessary repairs or take the necessary steps immediately. We specialize in both residential and commercial air conditioning. In addition to this, we also specialize in heating systems and plumbing systems. R

egardless of what types of issues you are experiencing – or where – we here at Reynolds are capable of assisting you! Contact us today at: 765-966-0994

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