How to Remove Musty Smell from Air Conditioner: Simple Expert Tips

Air Conditioning

As the weather starts to warm up, it’s time to turn on your air conditioner to keep your home comfortable. However, if you notice a musty smell when turning it on, it can be a cause for concern. Musty odors often indicate something is amiss within your cooling system. Which is why some will wonder how to remove musty smell from air conditioner. Particularly a window air conditioner.

A musty smell coming from your air conditioner can be caused by various factors, such as mold growth, dirty filters, or obstructed vents. It is essential to identify the root of the problem to prevent any potential health issues and ensure your system is functioning efficiently. The following steps will help you diagnose and address the issue, restoring a fresh atmosphere in your home.

By regularly maintaining your air conditioner and addressing any issues promptly, you can ensure a clean and healthy environment for yourself and your family. Read on to learn more about troubleshooting the problem and getting your air conditioner back in tip-top shape.

how to remove musty smell from air conditioner

Identifying the Cause of Musty Smell

When trying to remove a musty smell from your air conditioner, it’s crucial to first identify the cause. There are several primary reasons behind the musty odor, which can be narrowed down to the following sub-sections.

Mold and Mildew Growth

Mold and mildew can thrive in damp environments, often resulting from excess moisture in your air conditioner. When mold and mildew grow on the evaporator coils or within the ducts, they can release a musty odor. Regularly inspecting your AC unit and cleaning it can help prevent mold and mildew build-up.

Clogged Condensate Drain Line

Your air conditioner produces condensation, which is typically drained through the condensate drain line. If the drain line becomes clogged with debris or algae growth, it can lead to a full drain pan, causing water to overflow and produce a musty smell. Periodically check and clean your condensate drain line to ensure proper water flow.

Dirty Air Filter

A clogged or dirty air filter can obstruct airflow, causing dust, particles, and moisture to accumulate in your air conditioner. This build-up can lead to mold growth and musty odors. Replacing or cleaning your air filter regularly will help maintain cleaner airflow and prevent foul smells.

Excess Moisture and Humidity

High levels of moisture and humidity can cause condensation to form, increasing the possibility of mold and mildew growth. Basements and attics may be particularly prone to excess moisture. Investing in a dehumidifier or ensuring proper ventilation can help control humidity levels and reduce the risk of musty smells.

Knowing the possible causes of musty smells in your air conditioner will allow you to better address the problem. It’s essential to maintain and inspect your AC unit routinely to minimize mold growth and other potential issues.

General Inspecting and Cleaning of the Air Conditioner

First we’ll go over what it will take to clean your window air conditioner. If this seems like a job you can tackle as a DIY’er, than a more detailed explanation is farther down in the article.

Cleaning the Evaporator Coils

Start by unplugging your air conditioner and accessing the evaporator coils. These coils can accumulate dirt and debris, which can cause odors. Carefully clean the coils with a brush or soft cloth. If there’s stubborn buildup, you can mix a mild detergent with warm water and gently scrub the coils. Rinse thoroughly and let them dry before reassembling the unit.

Maintaining Air Filters

Air filters play a crucial role in preventing dust and debris from entering your air conditioning system. Check your air filter regularly and replace it if it’s dirty or damaged. Some filters are washable and reusable, so make sure to follow the manufacturer’s instructions for proper cleaning and maintenance. Clean filters will reduce unpleasant odors and improve the efficiency of your air conditioner.

Unclogging the Condensate Drain Line

The condensate drain line removes excess moisture from your air conditioner. Over time, this line can become clogged with dirt and algae, causing musty odors and potentially damaging your unit. To unclog the drain line, use a wet/dry vacuum or a drain line brush to remove any blockages. After clearing the line, you may want to pour a mixture of water and white vinegar down the drain to prevent future clogs.

Checking the Drain Pan

Inspect the drain pan for leaks, rust, or damage. If you find any issues, you should replace the pan to prevent water damage and unpleasant smells. Additionally, clean the drain pan regularly to remove any standing water, mold, or mildew that may be present.

Cleaning the Vents

Finally, examine the vents and ductwork for dust, debris, or mold. Use a vacuum with a soft dusting brush attachment to gently clean the vents. Regularly cleaning your vents and ductwork will help eliminate musty smells and improve your air conditioning system’s efficiency.

A Detailed Guide to Cleaning Your Window Air Conditioner

Whether you’re an ardent DIY enthusiast or a busy homeowner, cleaning a window air conditioner might sound like a daunting task. But I’m going to share some critical things do’s and don’ts so you can handle this task yourself.

Getting Started with the Cleaning: Inside First

When it comes to cleaning the inside of your window AC, it all starts at the front. All you need is to remove a few screws and lift the front panel off. The first thing that you might notice is the modest air filter, which unfortunately doesn’t catch as much dust as you’d hope. It’s recommended to clean this filter with warm soapy water.

As you lift the front end, you’ll notice some dirt and grime build-up. Surprisingly, a small dirt accumulation (as thin as 1/100th of an inch) on your AC coils can decrease your system’s efficiency by 5%. So, it becomes crucial to keep your coils clean.

Using a Foaming Cleaner

The use of a foaming cleaner can work wonders for your window AC. Some might doubt spending money on this cleaner, but it does make a difference. Many cleaners will often come with a small brush at the end that further aids in cleaning. The foam helps to lift the dirt and grime, which can then be wiped off with a towel.

After applying the foam, wait for about 10 minutes, and rinse it. While some might argue that rinsing isn’t necessary, using hot water to spray in between the coils to rinse out the detergent can give better cleaning results. Remember to stay away from the electrical parts during this process.

Moving On to the Outside

Just like the inside, the outside of your window AC unit needs cleaning too. Using the same foaming cleaner, apply it evenly on the outside. Wait for about 10 minutes, and then rinse it off.

Although the outside of the unit might appear clean, the reality could be different. The air that travels from inside out traps debris within the coil, causing an efficiency drop. That’s where a foaming cleaner comes in handy, as it penetrates deep inside the coils, breaking down the dirt and grime. However, for more severe dirt accumulation, you might want to up the pressure and use a powerful rinse, being careful not to damage the fins.


While cleaning your window AC can seem relatively straightforward, there are some things you should avoid.

  1. Avoid excessive water use: Overfilling the drainage tray could cause the water to flow back inside the unit.
  2. Let the unit drain: Do not run the unit until it is fully drained, or you’ll end up with a soapy water mess.

By following these steps, you can enjoy a more efficient, cooler, and healthier environment. Remember, maintenance is key for your air conditioning system to run smoothly and efficiently. Happy cleaning!

Leave a Comment