Window AC Smell Like Fish: 5 Causes With Killing Solutions

Are you experiencing an unpleasant fishy smell coming from your window air conditioner? You’re not alone. 

This issue can be quite frustrating, but fear not, as we’re here to help!

With our expertise and years of experience in the field, we have encountered numerous cases of window ACs emitting fish-like odors and successfully resolved them.

Here we are going to share with you. In this post, we’ll explore the reasons behind a fishy smell in window AC and provide solutions to get rid of it.

Why does the window air conditioner smell like fish? 5 Causes

Through our years of experience in addressing fishy smells in window air conditioners for our customers, we have compiled the 5 common causes behind fishy smelling window AC units. Here they are:

Microbial Growth:

microbial growth in window air conditioner

Believe it or not, microbial growth in your window AC is the most common cause of fishy smell from your air conditioning unit.

Moisture, dust, and debris inside the AC unit create an ideal environment for microbial growth, including bacteria and mold. These microorganisms release volatile compounds that can produce a fishy smell. 

Regular cleaning and maintenance of your window ac unit, including cleaning the coils and filters, can help prevent microbial growth and help eliminate that fishy odor coming from your unit.

Clogged Condensate Drain:

window ac smell like fish due to Clogged Condensate Drain

The condensate drain is responsible for removing water produced during the cooling process. If this drain becomes clogged with dirt, debris, or algae, it can lead to stagnant water accumulation.

The presence of stagnant water emits a fish-like odor from your window AC unit. Regularly cleaning and clearing the condensate drain can prevent the clogs and ensure that the stagnant water doesn’t linger within the drain and keep your air conditioning smelling fresh.

Related: drain a window air conditioner

Overheating of Electrical Wires:

melting of Electrical Wires in window ac can cause fishy smell

In some cases, a fishy smell from a window air conditioner may be caused by the overheating of electrical wires.

When the electrical components of the air conditioner become overloaded or malfunction, they can generate heat, potentially leading to burning or melting of the wires.

The burning smell produced by overheating wires can sometimes resemble a fishy odor.

Improper Ventilation:

Good airflow is key! Inadequate ventilation around the AC unit can contribute to the fishy smell. Insufficient airflow prevents moisture from being effectively removed, leading to increased humidity levels within the unit. 

This high humidity can create a favorable environment for microbial growth, which can produce the fishy odor.

You can ensure proper ventilation by installing your window ac properly on window and by keeping the area around the unit clear and unobstructed.

Presence of Dead Animals or Pests:

Presence of Dead Animals or Pest in window ac

Yep, this one can be a bit unpleasant. Another possible cause of a fishy smell from a window air conditioner is the presence of dead animals or pests. 

Sometimes, animals or pests can find their way into the air conditioner unit and become trapped or perish inside.

As their bodies decompose, they release a strong and unpleasant odor that can resemble a fishy smell.

How to Prevent Fishy Smells in Window Air Conditioners?

Preventing those fishy smells in your window air conditioner is super important for a bunch of reasons. Trust me, after dealing with countless fishy-smelling AC units, I’ve learned two things. 

First off, nobody wants to hang out in a room that smells like a fish market, right? It can be downright uncomfortable. But here’s the kicker: those smells often indicate that something’s not quite right with your AC unit. 

So, taking some proactive steps to prevent those odors will not only keep things fresh but also ensure your air conditioner is in tip-top shape.

Let’s dive into the nitty-gritty of keeping your window AC smelling great with some tried-and-tested methods based on my experience:

Regular Cleaning and Maintenance

Regular cleaning and maintenance are key to preventing fishy smells in window air conditioners. Here are some essential steps to follow:

1. Clean the air filter and keep it clean

Cleaning your air filter and keeping it clean is a biggie. They work hard to catch all the dust and yucky stuff in the air, but over time, they can get clogged and cause airflow problems.

So, make a habit of cleaning or replacing those filters regularly to prevent fishy smells from your window ac.

2. Clear the Clogged Condensate Drain

Clearing a clogged condensate drain in your window air conditioner is an important step to prevent the occurrence of fishy smells. 

If the drain gets clogged, water starts pooling, bacteria start breeding, and fishy smells appear. According to, you should clean your window ac drain line at least once every three months.

3. Remove the Mold and Mildew from your window AC

Mold and mildew love the moist environment of an air conditioner. These troublemakers not only create those fishy smells but can also mess with your air quality and allergies.

But fear not! You can take control and show your AC unit some tender loving care. All you need to do is roll up your sleeves and give it a good cleaning.

Here’s the secret: focus on the coils, drip pans, and other parts inside your AC that tend to collect mold and mildew.

By cleaning these areas regularly, not only will this eliminate the fishy smells, but it will also improve the air quality in your space, making it much nicer to breathe.

Deodorizing Techniques for Your Window AC To Eliminate Fishy Smells

Now, let’s talk about some deodorizing tricks that can help eliminate fishy smells from your window air conditioner and make sure your unit smells fantastic:

Using Natural Remedies

Did you know that vinegar, baking soda, and lemon juice can be your secret weapons against unpleasant odors? 

It’s true! Place a bowl of vinegar or sprinkle baking soda near your AC unit to absorb and eliminate those fishy smells. 

For an extra burst of freshness, mix lemon juice with water and spritz it on the air filters. Nature’s power at its best!

Using Commercial Deodorizers

Sometimes, commercial deodorizers made specifically for air conditioners can be a game-changer. 

These bad boys contain special odor-neutralizing agents that freshen up the air and mask any unpleasant odors. 

Professional Servicing

And finally, if all else fails, don’t hesitate to call in the pros. A professional servicing of your window AC can do wonders. 

They have the expertise to give your window AC a thorough cleaning and inspect for any underlying issues. 

Trust me, regular professional maintenance not only keeps the smells away but also prolongs the life of your beloved air conditioner.

So, with these tried and tested tips from my years of experience, you can conquer those fishy smells and enjoy a breath of fresh air from your window air conditioner!

Next to read: quietest 12000 btu window air conditioner 2023

Tips to Avoid Fishy Odor-Causing Situations:

Here are some tips to help you avoid fishy smells in your window air conditioner:

  • Keep the area around your window air conditioner clean and free from dust, dirt, and debris. Regularly vacuum or sweep the space to prevent these particles from entering the unit.
  • Avoid placing strong-smelling items near the air conditioner, such as dirty laundry, pet beds, or trash cans.
  • If you notice any water leakage or excess moisture around the unit, address it promptly to prevent mold and mildew growth.
  • Minimize smoking or using strong chemicals in the vicinity of the air conditioner, as these can leave lingering odors.

Related: air conditioner sounds like running water

FAQs, Window AC Smell Like Fish

Q1. Can I use air fresheners to eliminate fishy smells in my window AC?

Ans: Yes, you can use air fresheners to eliminate fishy smells in my window AC. However, air fresheners may temporarily mask the odor, but they do not address the underlying cause. It’s best to focus on proper cleaning, maintenance, and deodorizing techniques to eliminate fishy smells effectively.

Q2. What should I do if the fishy smell persists despite cleaning the unit?

Ans: If the odor persists despite cleaning the unit, it is recommended to seek professional servicing for your window air conditioner. An HVAC technician can thoroughly clean and inspect the unit to identify any underlying issues that may be causing the smell.

Q3. Should I cover my window AC during the offseason to prevent odors?

Ans: It is advisable to cover your window AC during the offseason to protect it from dust, debris, and potential odor-causing factors. Use a cover specifically designed for air conditioners or consult the manufacturer’s recommendations for proper storage.

Q4. Can cooking near the air conditioner contribute to the fishy smell? How can I avoid this issue?

Ans: Absolutely! Cooking near the air conditioner can contribute to the fishy smell. The strong odors from cooking can get absorbed by the AC unit, causing it to circulate and spread the smell. To avoid this issue, make sure to cook away from the window AC unit and ensure proper kitchen ventilation.

Q5. Can the fishy smell in the window AC be harmful or pose any health risks?

Ans: The fishy smell in your window AC is usually just unpleasant but not harmful. However, if you start experiencing things like coughing or allergies along with the smell, it’s a good idea to get some professional help.

My last note on fishy smelling window AC unit

Preventing fishy smells in window air conditioners is achievable through regular cleaning and maintenance, deodorizing techniques, and following simple tips to avoid odor-causing situations.

By taking proactive steps, you can ensure your air conditioner is free from unpleasant fishy odor.

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David Jack

David Jack

David Jack is a veteran when it comes to air conditioners, he love helping people find solutions to their problems with AC units. His specialty is helping people find the right Air-Conditioner for their needs, whether that means replacing a broken unit or adding on to an existing system. He is also great at diagnosing problems and fixing them quickly. He learned this from my father Jack Smith who was an air conditioner repairer, he has 2 years of experience in this field.

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