Have you ever noticed a typical foul or burning smell from AC unit? Have you ever thought that it could be dangerous as well? Many familiar smells come out of the AC unit. Generally, this typical smell has some specific indication about the health of your AC.

The present article is all about what causes burning smell from AC, which also provides information about the standard most 6 smells from the AC unit.

Read the below article to know about what causes burning smell from AC.

What causes an awful smell from AC?

What causes an awful smell from AC?

Several odours come from your AC indicate that your AC unit is not in perfect condition. This foul smell usually signifies and suggests about the health of your AC unit. It is harmful to your health too.

Even worse than that, some occurs are toxic and require urgent attention. The foul smell doesn’t need to mean an urgent repair of your AC unit is needed. Let’s first discuss the most 6 familiar smells from the AC unit.

1.  Burning or Electrical Odours

Electrical smells are typical air conditioning smells and mainly indicate a mechanical problem with the air conditioner compressor or fan, electrical failure, or a wiring issue.

The major components of the AC unit are made from various chemicals and metals, and prolonged exposure to odours is not healthy. The first few times any air conditioner starts on, it may emit a burning odour that can smell electrical or dusty.

Usually, after 15 to 20 minutes, the smell will automatically dissipate. If it does, then it is probably burning off the dust in the unit. Which is expected after the team has not been in use for a while.

Electrical smells are typically a problem with the compressor of the AC unit and fan motors or wiring.

2.  Gunpowder Smell

The gunpowder smell from the AC unit is very similar to electrical odors. Distinctive gunpowder-like aromas can be due to a fried fan motor or circuit board. Again, as significant AC unit components are made from various metals and chemicals can pose potential dangers to your respiratory system.

3.  Rotten meat Smell

If you smell like foul sulphur or it smells like rotten meat depicting from your air conditioning unit, it is most likely to have a natural gas leak from the AC unit. Although gas is majorly doorless, the utility person providers add the aroma to alert people of a dangerous leak. So, if you smell gas, there can be a significant problem. 

Another primary reason for these types of AC smells you may have a pest problem or dead mice or lizards somewhere in your ductwork or attic.

Suppose it’s your case leak, then you should be more cautious and not take it lightly. Low-level exposure to the gas is mildly very harmful to your health. Extreme high levels of gas smell consumption can reduce oxygen in your bloodstream and lead to a loss of consciousness and even death.

4.  Exhaust Fumes smell from Air Conditioner.

Exhaust fumes can strongly indicate fluids leak from specific components in your AC or heating systems.

Burning oil smell and other fluids released from the AC unit in large amounts have toxic effects on the environment. They are liberated in the form of gas. This gaseous component can be different in its chemical structure as it is in its original liquid state.

These particulates and features of the chemical structure can be very harmful to your health when inhaled, depleting and disturbing oxygen in your bloodstream, resulting in many serious health issues.

5.  The chemical odour from the AC unit

Chemical smells can come from many various sources.

Open Chemical Containers

The AC might not even be the culprit of the smell. Open chemical containers located near an air conditioning unit can intake, or ductwork could be the source. Once picked up in the airflow, which can lead to a pungent chemical smell from the Ac unit.

6.   The AC unit itself- 

If your AC unit smells like paint thinner or a fruity smell like formaldehyde, or any other chemicals components, it needs to be assessed before it is used. Many fluids are used within your AC unit. They can be the main culprit for an assortment of chemical-type smells when the unit malfunctions. 

7.  Ozone Smells from the AC unit.

Electrostatic air filters can produce ozone the smell, and emanate an odour like chlorine. Also, certain types of UV lights installed in the Ac unit to irradiate filter surfaces to kill bacteria can produce an ozone-like smell. Ozone is very unhealthy and harmful for people if inhaled in large enough amounts. Some people can also experience chest pains, while others may have trouble breathing.

8.  Glue Odours from AC unit

If your AC has recently gone under any ductwork done, the main reason for the chemical smells may be the solution and chemicals used in the repairement. The glue, a chemical component used for duct installation, can give off a heavy chemical smell while it is drying.

9.  Freon Leaks from the AC unit

Freon is a chlorofluorocarbon or CFC, which is also known as a refrigerant. Freon is the main component that removes heat from the room and transfers it to somewhere else in the environment. This is what keeps you cool inside.

Freon passes within a closed system in a condenser compartment and evaporator coils.

Mostly this system is made from copper. These coils and lines can sometimes lead to crack and result in a refrigerant leak.

Freon leaks can be toxic. If you suspect any freon leaks from your AC unit, you should call for a professional.

What does Air Conditioners’ foul smell indicate?

There are some specific signs and invitations when your AC unit is smelling bad. We have listed here some of the indications like-

  • Often the smells indicate that the system needs a service. 
  • more severe odours like sulphur or gas indicate a much powerful and vast problem. 
  • If you notice an electrical or burning smell from your AC unit with some start-up issues, it is your compressor unit problem.

Also Read – Are air purifiers a waste of money

Five most common causes of burning smell from AC

As we have understood the most common types of different smells from the AC unit, we focus on the burning smell from the AC unit, which can trigger your tension and stress. Usually, when there is burning smell from the AC unit, most of the common problem or issue is related to the AC compressor unit.

Here we are with the most common five causes of burning smell from AC. we have also compiled our information into three main categories: their primary reason, signs, and solution.

Several different issues, including: could produce a burning smell from Ac.

A dirty or clogged air filter

  • Signs: Your air filter hasn’t been replaced in a while.
  • Reason– 
  • A clogged or a dirty filter can block the airflow to essential components of your AC unit, like the blower motor. 
  • With less air passing into the system, your blower motor needs to work longer to cool your room. 
  • This can lead to impaired stress on your engine that it overheats, producing a burning smell.
  • Solution
  • Well, if the unit’s air filter is noticeably dirty and clogged, you should replace it with a clean and healthy filter as soon as possible by the professional.
  • However, if you’ve tried changing the filter and still the smell persists, your blower motor might need to be replaced.
  • Other reasons like reduced airflow were not the issue. You need to contact your professional to have a look into the unit and diagnose the problem.

Worn out bearings

  • Sign: You can hear strange high-pitched grinding noises when your AC is working.
  • Reason-
  • Your AC unit has two fans: one in the inside unit and one in the outside unit. 
  • Motors power both fans. 
  • Eventually, the motors’ bearings can wear out due to maybe overload, which produces a burning smell.
  • Solution-
  • A professional can usually handle this issue by lubricating the bearings mechanism inside the motor unit. 
  • By lubricating the bearings, you can keep the engine from burning out and spare yourself the costly inconvenience of replacing the motor altogether.
  • Remember that there may be permanent damage to the bearings and the motors, which might require a more extensive repair.
A worn fan-belt
  • Signs-
  • You have an older AC system or unit.
  • The odour smells like burning rubber or rubber components.
  • Reason-
  • People who own older and outdated versions of the Ac unit may have a belt-driven blower fan. 
  • If you do own that, and your AC smells like it’s burning rubber, your fan belt might need to be replaced or maybe repaired.
  • The fan belt, made of rubber, works to spin the fan blades, which pass air throughout your home. 
  • Over time, the belt component can become weak or wear out completely. 
  • Eventually, the fan belt will lead to overheat and create a burning rubber smell.
  • Solution-
  • If you think that the fan belt is the main culprit, you should shut off your AC unit and contact a professional to replace the strap for you.

Electrical issues within the AC unit

  • Signs-
  • Your AC smells like burning plastic.
  • Reason-
  • Your AC unit has electrical wiring, typically has a plastic coating around it.
  • Anything from worn-out electrical connections to faulty breakers and short circuits can cause the plastic coating on wires to melt, resulting in a burning plastic smell. 
  • This can potentially cause significant damage to other AC unit components and even start an electrical fire.
  • Solution-
  • If there is a noticeable and robust smell of burning plastic in your home, you should immediately shut down your AC system and contact a professional technician. 
  • The technician will check your whole unit thoroughly to locate and remedy the faulty/melted electrical equipment.

A bad capacitor

  • Signs- 
  • The odour smells like burning plastic.
  • Reason-
  • Due to old age, capacitors tend to go wrong because of overheating, power surges, or simple deterioration. In any case, if the capacitor goes wrong, it can cause the motor to overheat, which creates that strong burning smell.
  • Solution-
  • If the capacitor is wrong, you will need to go for capacitor replacement or a motor replacement.
  • Call for a professional technician to work skilfully and do not try by yourself to solute the issues.


Q.1 Why does my AC smell like a burn?

A faulty or damaged motor can lead to a build-up of dust or a lack of lubrication – both of which can lead to overheating and, as a result, a burning smell. If the issue stems from the air conditioner motor, you will likely need to contact a professional to repair or replace the mechanism.

Q.2 Why does my AC smell like burning plastic?

You may smell the burning plastic because there are plastic components located near the wiring. This may be due to defective breakers, old or worn electrical connections, or short circuits. If this occurs, turn your AC system off immediately and contact your local HVAC professionals.

Q.3 How do you get the burnt smell out of an air conditioner?

Yes, you can use your air conditioner unit to remove unpleasant smells from your house or home. The easiest way is to open the windows and then start the air conditioner on “ventilation” mode with the higher fan speeds. This will exhaust the smells slowly out of the house or home in some time.

Q.4 Can a dirty or clogged air filter cause a burning smell?

If your filter is clogged or dirty, it will force your air handler to work overtime. This can result in your blower motor overheating and give off a burning smell under overloading stress carried throughout your ductwork and into your living spaces.

Q.5 What does burning freon smell like? 

Freon is a chlorofluorocarbon-CFC that helps the AC remove heat from the atmosphere to keep you cool and comfy, but it can be harmful to people if it is not appropriately contained. A freon leak will produce a smell between sweet and chloroform. Freon leaks can be toxic.


The burning smell from the AC unit has many reasons. It is tenacious and harmful for people to inhale. Proper maintenance and servicing of your AC unit are necessary to keep it healthy and work efficiently.

Please read the above article on what causes burning smell from AC and avail some basic information about their signs, reasons, and solutions.

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