A portable air conditioner can be a great alternative to a central air conditioning system or a window unit. Not only does it provide you the flexibility to move it around and cool different parts of the home, it will remain trouble-free for the most part. Yet, when not taken proper care of, a portable air conditioner may start to smell. As soon as you turn it on, you will be hit by a foul, musty odor. The odor is not just repulsive but can affect the performance of the air conditioner negatively. Not to forget that it poses genuine health concerns for you and your family.

So, if your portable air conditioner starts smelling, you have to try and nip the problem in the bud. That is only possible if you know the causes as well as some ways to prevent it. Let's go over each in detail:

What Are the Causes of an Air Conditioner's Odor?

The main cause of odor emanating from an air conditioner is lack of proper cleaning and maintenance. If you don't look after your portable AC, there is a good chance that an odor will emerge from it someday. Here is a look at the causes of odor from an air conditioner:

  • Clogged Filter: Among the most common reasons of a foul odor emanating from your portable air conditioner is a clogged filter. The filter inside the air conditioner gets covered with dust and other small particles over time. The purpose of the filter is to keep this debris out from other parts of the air conditioner. But, there comes a time when the debris buildup is beyond a certain limit and the air conditioner starts to smell. Moreover, a clogged filter does not let air pass easily through the air conditioner. This not only intensifies the odor, but can also hamper the performance of the appliance. The filter can become more clogged if you have pets in the house. The advantage and at the same time the problem with portable air conditioners is their easy accessibility. Pets can get close to the unit, which lets their fur get into the system and clog up the air filter.
  • Mold & Mildew: The internal components of a portable air conditioner become moist whenever you turn it on, especially if you like in a humid place. In addition, if the unit is not cleaned properly, the accumulated dust combines with the moisture. This leads to the growth of bacteria that eventually turns into mold and mildew. It is the perfect breeding ground for bacteria which cause molding, thereby highlighting the importance of keeping your portable air conditioner clean. The issue is that mold & mildew can grow and spread to any part of the air conditioner. So, if you suspect it is the root cause of the odor, you might have to check every component.
  • dirty air filterLack of Upkeep: As mentioned above, the primary reason for your portable air conditioner smelling is the lack of upkeep. If you don't take clear your air conditioner, it will likely develop mold or have a clogged air filter. Simply, regular cleaning can also make a huge difference, not just in terms of preventing odors from emerging but also enhancing the useful life of your portable air conditioner.
  • Size of the Room: Not many people are aware of the fact that the size of the room also determines the performance of a portable air conditioner. It is generally smaller than an AC installed in a room but sometimes the room you keep it in might be too small for the AC. For instance, if your portable AC has 14,000 BTUs of power and the room requires only 10,000 BTUs, it won't be able to dehumidify the air because it will cycle on and off too quickly. This gives rise to a murky, moldy smell.
  • Refrigerant Leak: If you feel the smell coming from your portable air conditioner is like gas, there is a good chance the refrigerant gas of the AC might be leaking. You have to get it checked to be on the safe side. If the refrigerant is indeed leaking, it could be causing the smell. In this case, you will need to have the leak plugged and get the gas refilled. On the other hand, if the smell is 'sweeter', it may be caused by any other liquids leaking, such as antifreeze. If you can't seem to put your finger on the root cause of the odor, you should consider the possibility of a leak.
  • Running on 'Low': Running your portable AC constantly on the 'low' setting can also cause odor. According to manufacturers' specifications, if an air conditioner is not used to its full capacity, it fails to dehumidify the air, eventually leading to a murky smell coming from it. So, on occasion, amp up the power of your AC and let it operate on full blast.

These are some common causes of odors in a portable air conditioner. As you can see, nearly all of them have to do with the internal unit and components not being clean. This gives you a sure shot clue as to what needs to be done to ensure your air conditioner doesn't smell.

What are Some Quick Remedies to the Problem?

Once your portable air conditioner starts to smell, you have to act quickly to deal with the problem. If you leave it like that for too long, you risk causing damage to your AC. Not to mention, the odor you will have to deal with every time you turn it on and possibly dealing with a health hazard. Therefore, the ideal way to deal with the problem is by applying some quick remedies, such as:

  1. First and foremost, you should clean the drain line. On portable ACs, the drain line is a tube that is located on the outer side of the unit. Find the pipe and clean it using the following instructions. Make a mixture of one part bleach in three parts water and clean the drain with it thoroughly. This will remove any mold, mildew or debris that might be causing the odor. Of course, if this doesn't cure the problem, you have to move on to the next step.
  2. Remove the lid of the portable AC and inspect the coils. Use a flashlight so you are easily able to spot debris, mold or anything else which may be causing the smell. Once you undo the lid, it will be quite clear to you whether the odor is coming from the inside of the air conditioner or not. Clean it thoroughly with a damp cloth to ensure that nothing is sticking to it.
  3. Change the air filter. Unless you put in a new filter recently, it is likely that the odor is being caused by the buildup of dust and debris on the air filter. In that case, the correct option is to replace the air filter and put in a new one. If it was causing the problem, the odor should go away in a matter of minutes.

What are Some Ways of Preventing Odors in Your AC System?

Rather than waiting for the problem to grow to a level where your AC system starts to smell, it is best to prevent it from happening in the first place. There are some basic measures you can take to prevent odors in your portable air conditioner, including:

  • My Air Conditioner Smells
          Maintain your portable AC. If you maintain it yourself or get a professional to do it, any problems which may lead to an odor from the AC will be detected at the earliest stage. This way, you can deal with the problem before it intensifies. So, add the maintenance of your portable air conditioner to your to-do list.
  • Clean the air conditioner inside and out. Using the manual, learn to unscrew the main housing of the unit to get access to the internal components. Once open, you have to clean each and every part thoroughly. Clean the AC regularly, depending on the volume of use. For instance, if you use your air conditioner every day, which is quite likely in the summer, you should clean it at least once a month. Otherwise, cleaning the AC once every two months is sufficient.
  • Replace the air filter of your portable AC every few months. Though you can extend its useful life by cleaning it thoroughly, cleaning the air filter is an integral part of the process. Therefore, when the air filter gets too clogged up in your opinion, replace it. Also, keep an eye on the other replaceable parts of the portable air conditioner, such as the drain filter. Dust and debris usually accumulate on them, rendering them unusable. Even if you clean them out, they don't perform at the level they did when new.
  • The evaporate coils, air filter and drain lines are the parts of your portable air conditioner most likely to be affected by mold and mildew. Bacteria gets into the machine and start spreading. Over time, the portable AC will start smelling because of the mold. The best way to prevent this is thoroughly clean these parts on a regular basis. This way, the risk of bacteria taking hold and breeding in there is minimized.
  • Run your portable AC on 'Fan Mode' for a few minutes from time to time. While this won't cool your room, it definitely helps release the moisture and humidity that have built up inside the air conditioner over time. This is a great way to prevent mold and mildew. So, make it a point to run your AC on 'Fan Mode' at least once a week.

These are some ways you can prevent your portable air conditioner from smelling. Keep these pointers in mind so you aren't greeted by a murky stench every time you turn your AC on. It will ruin your experience of enjoying the cooling the AC provides and will also affect the ambience of the room you have placed the AC in.

So, if your portable air conditioner starts smelling, you will know the probable causes. Regardless of whether you want to tackle the problem on your own or call professionals, diagnosis is much easier when you know the general causes. The information to deal with the problem has also been provided to you along with ways you can prevent the odor in the first place. In other words, you are now equipped with the knowledge you need to make optimum use of your portable air conditioner and enjoy its cooling power for a long time to come without facing the risk of odor or poor performance.

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1 comment

  • Well, cleaning is a general task for the average person, so this article is not really telling anything new.

    I found the only item worthwhile to be the mixture between bleach and water, and to clean the drain line. My unit does not have a drain line, just a container with a rubber plug. So I have to spray in some mixture into the tank and see if this helps.

    Other than that, my unit has always been operated and maintained according to manufacturers’ recommendations, yet still developed a bad smell that I can not get rid of.

    Consumer2019 on

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