What Are The Causes Of A Burning Smell Coming From An AC?

Burning smell coming from the AC can be worrying. At first, you might be thinking that the unit is about to catch fire. On top of that, the unpleasant odor adds to the already frustrating issue. There could be several reasons causing a burning smell from the AC and an HVAC repair service can inspect the unit to find out the cause. To start it yourself, let’s take a look at the possible causes along with the fixes of this issue.

Dust Burning Off

The first possible reason your AC might be producing a burning smell is dust build-up and burning. This usually happens when the unit has been sitting for a while and dirt and dust accumulation takes place. If you live in a region where air conditioners are not used throughout the year, the unit is supposed to remain dormant for a few months.

During the break, birds and mammals tend to take accommodation in the outdoor unit that brings huge amounts of dirt and dust. Furthermore, extreme weather conditions such as thunder and dust storms cause dead branches, leaves, and shrubs to end up inside the unit as well.

That said, if you were to turn the air conditioner on after a while, you can expect a burning smell as the dirt and dust on the components begin to burn. The best way to prevent this situation is by covering the air conditioner. Plus, you should keep the air conditioner cleaned and maintained by a professional even if it is not in use.

Dirty Air Filter

Another possible reason your ac is giving off a burning sensation is a dirty air filter. Depending on the unit, it might have one more multiple air filter. Regardless, it is important that the air filters are clean to prevent complications down the road.

Air filters are designed to trap contaminants from the air before it is distributed inside the house. With time, the air filters are supposed to get dirty and clogged if ignored. Part of maintaining and cleaning the air conditioner entails keeping the air filters clean as well.

If they are clogged, you might smell a burning odor that might be harmful to your family members, especially kids. Moreover, ignoring a clogged air filter can also cause overheating which might lead to permanent damage. To both fix and avoid the issue in the future, you should clean the air filters at least once or twice a month depending on the usage frequency.

And if needed, you should also replace the air filters if the unit is old and the filters have developed cracks or other visible signs of wearing out.

Broken Fan Belt

If you observe a burning smell coming from the AC accompanied by a squealing noise, it most likely means your AC fan belt is broken. Air conditioners tend to produce several types of noises that indicate a particular problem. The majority of the time, these unusual sounds are ignored by homeowners which leads to expensive repairs and replacements.

In addition to that, such unusual sounds are more common in old units. Lack of maintenance could also be the primary reason behind noisy AC parts. Therefore, as soon as you hear a squealing noise even if it is not too loud, you should immediately turn the air conditioner off instead of waiting for it to go away on its own.

If the fan belt is cracked, it might snap and damage the motor. This is why you should always be on the lookout for unusual noises and sounds. At the same time, opting for expert maintenance will help identify and fix such issues before they go out of hand.

Overheated Fan Motor

An overheated fan motor could also cause a burning smell coming from the AC. When the fan motor overheats, it can cause the insulation around the wires to melt and cause a burning smell. This is a serious issue that needs to be addressed immediately.

In this case, the first thing you need to do is turn off the air conditioner. Inspect the source of the burning smell and call an HVAC contractor Fairfax. Make sure that you unplug the unit from the main power outlet. Do not access the air conditioner if you are not aware of the basics.

A fan motor can heat up due to several reasons. Electrical components are relatively sensitive and sometimes give up for no absolute reason. If the unit is covered by warranty, you can try claiming the issue to get a free replacement.

However, in most cases, the main reason tends to be the age of the unit. As the unit gets older, the components turn weaker and the chances of overheating and other such issues increase.

Damaged Capacitor

The capacitor is designed to store electric charge and helps start the compressor of the AC. Like the fan motor, the capacitor could also overheat and produce a burning smell. Plus, the damaged capacitor also appears swollen. Electric surges are the main cause of damaged capacitors.

If the capacitor is damaged, you will notice some signs such as the air conditioner not starting up. It might perform in an unusual manner or simply shut down while running. However, there is no need to panic. All you need to do is replace the capacitor.

Then again, you should not go near such components and consult a professional. This will not only reduce the risk of injury but also help the expert identify and fix the root cause of the problem.

How To Prevent AC Problems?

Preventing ac problems depends on how well-maintained the air conditioner is. As mentioned earlier, professional maintenance is rare for the majority of the homeowners as they consider it an expense. But if you were to think about the benefits, it will surely come out as an investment.

It is a common misconception that professional maintenance is only about cleaning the unit thoroughly. In fact, it includes a thorough checkup of the unit as well to identify any replaceable or repairable components before they cause you discomfort.

Sometimes, there are no visual signs or sounds that alert you. It is only when the unit is accessed that the expert finds out something was about to go wrong. And most importantly, professional maintenance helps prolong the unit’s life.

Air conditioning units are fairly expensive and therefore, need to run as long as possible to make your money worth. That is why scheduling professional maintenance is the only way to avoid troubles in the future.

Electrical Failure

Apart from the fan motors and capacitor, there are other electrical components inside the unit as well that could overheat, fail and produce a burning smell. In such cases, you might hear popping noises and your AC will shut down.

Simply turn the air conditioner off and call a professional. Do not try to fix the issue yourself as it could lead to severe burns. Such electrical failures can pop unexpectedly and you should be prepared.


Your AC producing burning smell should not worry you as long as you know what to do. First, you should keep your unit professionally maintained by air conditioning companies Vienna. Plus, keep the tips mentioned above in mind to prevent expensive replacements. This will help avoid any issues when you need your air conditioner the most.

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