Why Your Aircon Smells Bad (And What To Do With It)

Of all the things in your home that should not emit an unpleasant odor, an air conditioner should be on top of the list. Just imagine turning on your AC and a bad smell wafts throughout your room. Yikes. As you turn off the aircon, you’ll wonder why it smells bad, and what you can do to fix it.

The bad smells coming from your aircon may come from different sources. It may be a dirty filter, a clogged drain line, burnt electronics, or dead critters that somehow got inside your unit.

In this article, we will describe the bad odors that air conditioners sometimes make, and how to get rid of them.

Common air conditioner odors (and how to get rid of them)

These are the most common bad smells that your aircon can emit, and how to solve this problem.

1. Smells like death

No, your air conditioner is not dying. However, there may be a dead creature somewhere in the body of your air conditioner.

If you want to prevent critters from going inside the body of your AC, you may want to cover your air conditioner when not in use. We’ve written an article about the aircon cover before. Go check it out!

The fix: you’ll have no choice but to take of your air conditioner and take out the carcass. You can do this on your own or call a technician to do it for you.

2. Moldy odor

Molds can grow inside your aircon and release spores (and odor) over time if you don’t maintain it well.

If you want to find the most common areas of mold growth within the aircon, the two culprits are the filter and the drain line.

2a. Dirty Filter

A thick layer of dirt and grime on the aircon filter can harbor molds especially if the air in your room is humid. As the molds grow, it releases spores throughout your room. Not only can this emit a bad odor, it can also cause allergic rhinitis.

The fix: If your filter smells like molds already, vacuuming it just won’t do. Instead, clean the air filter by washing it in light soap and disinfectant. You can also try a vinegar and water solution. Do not use a brush as it can ruin the filters mesh; use a wash cloth instead.

2b. Clogged drain

The drain pipe is a dark and damp place – perfect for algae and molds to grow in. Not only can this make water leak from the aircon, the smell can also be irritating.

The fix: Call an aircon cleaning service! If you DIY the solution, you may end up pushing the algae and the mold growth further down the line.

3. Burnt smell

If you smell a burn odor emanating from your aircon, turn it off immediately!

Burnt odors can only come from actual burning stuff. It could be because of the compressor, or the condenser fan, or the evaporator fan overheating. It could also be because there is a short circuit either with the electronics of the AC itself or a fault in your outlet. Whatever it is, turn off the aircon as well as its circuit breaker, grab a fire extinguisher just in case, and call a technician ASAP!

The fix: call a technician ASAP to have a look with your aircon. You may have no other choice but to replace it if something really did burn out.

4. Choloform-like odor

A faint choloform-like odor is indicative of Freon leaking from your aircon. Also look out for an oily residue on the unit or on the wall, as this confirms the leak of Freon and compressor oils from your system.

The fix: call a technician ASAP to have a look with your aircon. You may need to have your refrigerant recharged to keep your AC working.


A smelly air conditioner is easily preventable by cleaning your unit regularly and having it checked by a technician every year to keep it in tiptop shape.

Just remember that at the first signs of the odor, act on it immediately before it causes some health problems for you and your family. Do not try to mask it as well with sweet smelling air fresheners or essential oil diffusers. Solve the problem at its root!


Why Does My Air Conditioner Smell Bad? | 5 Reasons Your AC Might Stink. (2020, December 29). Air Experts Heating and Cooling. https://yourairexperts.com/blog/why-air-conditioner-smell-bad

1 thought on “Why Your Aircon Smells Bad (And What To Do With It)”

  1. Air conditioner smell indicates a number of things. It is important to have a basic knowledge of this as one might be able to detect the issue. Regular maintenance of the system is extremely important.

    Thanks for sharing this article with. It is very informative. I hope we will get more useful information from you in the future.


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