Why Does My Air Conditioner Smell Like Fish? [ 3 Causes & Solutions]

When people arrive home, it is not uncommon for them to notice a fishy odor coming from the air conditioner. But why does your air conditioner smell like fish?

In most cases, the fishy smell in your air conditioner is caused by an overheating electrical component. The garbage or the mold in your HVAC system could also be the source of the smell. 

In this post, I will illustrate each cause and solution of an air conditioning unit smelling like fish. Note that the fish smell could be a sign of danger, so you should exercise caution and take action immediately.

What causes the fishy smell in an air conditioner?

Even though your air conditioner blows air with a fishy smell, it doesn’t mean the foul smell is produced by the ac. It could be coming from somewhere other than the air conditioning system.

Overheating electrical component

overheated electrical component

The electrical component can usually withstand a certain amount of heat. However, if it is overheated, the plastic coating will burn and emit a fishy odor. The smell will then be drawn into your air conditioner through the intake vent and dispersed throughout the system.

It often happens at light fixtures, breakers, outlets, and electrical appliances. If you want to get to the bottom of it, it usually comes down to loose wiring, overloaded circuits, damaged insulation, and unexpected power surges.

The place that has an overheated component usually has a stronger smell than other places.

In my experience, this situation happens more in old houses since it doesn’t have a good electrical system with good safety features.

Beyond that, the internal parts in the HVAC system or ac may become overheated as well. You can turn off the HVAC system to see if the odor goes away.

Filthy internal parts

dirty air conditioner

Over time, the air filter and evaporator coil in the air conditioner can collect a thick layer of dust and dirt. In addition to that, the interior of ac could be humid because the excess condensation happens on the evaporator coil. 

The moisture, along with the contaminants, creates a thriving environment for mold, mildew, and bacteria. 

Some of these microbes can give off a smell that resembles a fish. When you turn on the ac, the smell will enter the room through the air. 

Garbage near the air conditioner

If you don’t take out the rubbish on a regular basis, it will give off an unpleasant odor that smells like fish. For example, you may happen to place your trash bin around your window air conditioner. The fishy odor can seep into the ac, making you mistake that your ac is the appliance that produces the smell.

How to get the fish smell out of the air conditioner?

Depending on the cause, you need to use different methods to get rid of the fish smell in your ac.

Take out the rubbish right away

Examine the garbage cans around your house. If any of them are near the air vents or the air conditioning unit, you should relocate them and remove the trash immediately.

Remember to open the windows to expel the unpleasant odor left in the room and turn on the air conditioner again to see if the problem is mitigated.

Call a certified electrician 

When an electrical component overheats, it can catch fire, which is extremely dangerous. Rather than attempting to diagnose and resolve the problem on your own, you should contact a licensed electrician as soon as possible.

Because they have the expertise and tools, the electrician can detect and repair the problem.

They will also assist you in identifying other overheating issues in your home.

Clean your air conditioner 

If none of the above methods work, the cause could be mold and bacteria in the ac.

Hiring a certified HVAC expert is preferable for those who have central air conditioning but lack the necessary expertise.

You can clean your air conditioner yourself if you have a portable, split, or window unit.

To begin, remove the air filter, rinse it under running water, and use a brush to remove any remaining debris. Replace it after it has dried and turn on the air conditioner to see if the smell has gone away.

If not, try cleaning the evaporator coil. Some coil cleaners are available on the market that can dissolve the grime and debris inside.

How to prevent the fishy smell in your aC from coming back?

Again, a fishy odor in your air conditioner may indicate that something is wrong in your home. As a result, you may not want to deal with it on a regular basis. There are some ways to avoid it in the future.

Keep the ac and vents away from the garbage

Garbage can continue to make a bad smell if you don’t deal with it every day. To ensure the odor will not disperse all over your home, keep it away from the air vents or air conditioners. 

Update the electrical system 

Because the fish smell is often caused by overheated electrical components, if you live in an old house, you should update the electrical system to reduce the likelihood of this happening. It is an effective method of preventing a fire hazard.

Annual electrical safety inspections

To keep your electrical system in top shape, conduct an annual electrical safety inspection, which can detect problems early on and avoid the fishy odor caused by any electrical components.

AC maintenance 

The internal parts in the air conditioner can fail, and they can become filthy over time. Both of these situations can lead to a fishy smell in the ac.

Hence, it is recommended to maintain your ac, regardless of the type, on a regular basis to remove the debris and keep the parts in a good state.


Your air conditioner smells like fish is not always due to the ac itself. The overheated electrical component is to blame in most cases. When the plastic coating on the wire is burning, it will produce a fish-like smell. 

You should contact an electrician immediately and don’t attempt to identify and fix the problem because it may trigger a fire.

Under some rare circumstances, the dirty air conditioner and garbage could also be the source of a fish-like smell. Cleaning the air filter or throwing away the garbage can solve the issue.

About The Author

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Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested dozens of products in person, like humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.

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