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Smart AC Solutions
Window Air Conditioners

Why Does My Window Air Conditioner Smell

ByRalph P. Sita Updated onJanuary 15, 2025

When your window air conditioner emits a burning smell, several common issues might be the cause. First, inspect the air filter, as a dirty filter can cause overheating, resulting in the unpleasant odor. If the filter is clean, check the condenser coils next, as accumulated dirt can also lead to overheating and a burning smell. If neither of these components is the issue, it could indicate that the air conditioner is defective and may need replacing.

In addition to a burning smell, window air conditioners can sometimes release a musty odor, often due to mold or mildew buildup on the coils. While this is usually not harmful, it can be bothersome. To prevent such odors, clean the unit regularly. Wipe down the coils with a damp cloth every few weeks and use a coil cleaner to remove stubborn grime. If the smell persists after cleaning, place a bowl of vinegar near the unit to absorb the odors. Alternatively, activated charcoal or baking soda can also help neutralize the unpleasant smell by simply being placed nearby. Regular maintenance and cleaning can help keep your air conditioner smelling fresh and running efficiently.

Why Does My Window Air Conditioner Smell

Credit: dengarden.com

Page Contents

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  • Why Does My Window Air Conditioner Smell
  • How Can I Get Rid of the Unpleasant Smell Coming from My Ac Unit
  • What Could Be Causing the Musty Or Mildew-Like Smell in My Ac Unit
  • Is It Normal for My Air Conditioner to Stink
  • How Do I Prevent My Window Air Conditioner from Smelling Bad in the Future
  • How to Clean Window Ac Unit that Smells Musty or like Dirty Old Sox!
  • Next Steps
    • Related Articles

Why Does My Window Air Conditioner Smell

When you first turn on your window air conditioner for the season, it’s not unusual for it to have a bit of a smell. This is usually due to dust and dirt that has accumulated on the unit over the winter months. However, if your unit continues to produce an unpleasant odor even after you’ve cleaned it, there could be another problem.

Here are some possible causes of a smelly window air conditioner and what you can do about them. One possible cause of a foul-smelling air conditioner is mold or mildew growth inside the unit. If this is the case, you’ll need to clean the unit thoroughly using a solution of water and bleach.

Be sure to dry it completely afterwards to prevent future mold growth. Another possibility is that your air conditioner’s filter is dirty or clogged. A dirty filter can cause musty odors as well as reduced airflow and efficiency.

Clean or replace the filter according to the manufacturer’s instructions. If neither of these solutions solves the problem, there could be an issue with the evaporator coils inside your air conditioner unit. These coils can become covered in dust and dirt over time, which can lead to bad smells coming from your AC Unit.

You’ll need to clean these coils carefully following the instructions in your owner’s manual (usually involving removing them and cleaning them with a brush).

How Can I Get Rid of the Unpleasant Smell Coming from My Ac Unit

If you are noticing an unpleasant smell coming from your AC unit, there are a few things that could be causing it. One possibility is that the filters in your unit are dirty and need to be replaced. Another possibility is that there is mold or mildew growing inside the unit.

If this is the case, you will need to clean the unit thoroughly. Finally, if your AC unit is not properly ventilated, smells can build up over time and become quite strong. To prevent this from happening, make sure to regularly check the vents and ensure they are clear of any obstructions.

What Could Be Causing the Musty Or Mildew-Like Smell in My Ac Unit

If you’ve noticed a musty or mildew-like smell coming from your AC unit, there are a few potential causes. One possibility is that the unit is simply dirty and in need of a good cleaning. Another possibility is that there’s mold or mildew growing inside the unit, which can happen if it isn’t properly ventilated.

If you suspect mold or mildew, you’ll need to have the unit professionally cleaned or replaced. Finally, if your AC unit is located in an area with high humidity, that could also be causing the musty smell. In this case, you’ll need to make sure the unit is properly ventilated and/or use a dehumidifier to reduce the moisture in the air.

Is It Normal for My Air Conditioner to Stink

If your air conditioner is making your home smell bad, there are a few possible explanations. The most common cause of a musty smell coming from an air conditioner is mold or mildew. These can grow on the evaporator coils, in the drain pan, or in other areas of the unit.

If you notice mold or mildew, clean it off with a solution of bleach and water. You may also need to have your ducts cleaned if there is mold growing inside them. Another possible explanation for a foul-smelling air conditioner is that it isn’t draining properly.

This can cause water to build up in the unit, which can lead to bacteria and other organisms growing inside it. If your unit isn’t draining properly, you’ll need to have a technician take a look at it to see what’s causing the problem. In some cases, simply cleaning out the drain pan will solve the issue.

Finally, if your air conditioner has been turned off for an extended period of time (such as over the winter), it may develop a musty smell when you turn it back on again. This is because dust and other particles have had time to settle inside the unit. To get rid of this odor, run the unit on its highest setting for awhile until all of the dust has been blown out.

How Do I Prevent My Window Air Conditioner from Smelling Bad in the Future

If your window air conditioner has started to produce an unpleasant smell, there are a few things you can do to try and eliminate the source of the odor. First, make sure that the unit is clean. If it has been a while since you last cleaned it, there could be mold or mildew growing inside the unit, which would cause it to smell bad.

To clean the unit, remove it from the window and disassemble it according to the manufacturer’s instructions. Then, clean all of the parts with warm soapy water and let them dry completely before reassembling the unit. If you have ruled out dirt and grime as the source of the odor, then it is likely that something is wrong with the cooling coils.

These coils are responsible for absorbing heat from the air in your home and transferring it outside. If they become dirty or damaged, they can start to produce an unpleasant smell. To clean the coils, first turn off your air conditioner and unplug it from its power source.

Then remove any debris or dirt that has accumulated on them using a brush or vacuum attachment. Finally, rinse them off with clear water and allow them to dry completely before turning your air conditioner back on.

How to Clean Window Ac Unit that Smells Musty or like Dirty Old Sox!

Next Steps

If your window air conditioner smells musty, the first thing you should do is clean it. Unplug the unit and remove the front panel. Clean the evaporator coils with a coil cleaner or a solution of water and bleach.

Be sure to rinse thoroughly and allow the coils to dry completely before replacing the panel and plugging the unit back in. If your AC unit still smells after cleaning, it may be time to replace the filter. A clogged or dirty filter can cause musty odors as well as poor air circulation.

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Ralph P. Sita
Author: Ralph P. Sita

Ralph P. Sita is a seasoned professional with deep roots in both the HVAC and tech industries. His family’s business, Ralph P. Sita, Inc., is a locally owned and operated HVAC contractor with over 42 years of experience, serving the DC, Maryland, and Virginia areas. The company specializes in residential, commercial, and industrial heating, ventilation, and air conditioning services, offering everything from installation and maintenance to custom ductwork and indoor air quality solutions -www.ralphpsita.com. A former CPA, he spent the last decade as co-founder and co-CEO at Cybrary, a leading platform for cybersecurity and IT training. Cybrary became the largest, most well-known cybersecurity training businesses in the industry under his leadership. Smart AC Solutions is an opportunity to give back to the HVAC community by providing reliable, actionable information on all things heating and cooling.

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Ralph P. Sita

Ralph P. Sita is a seasoned professional with deep roots in both the HVAC and tech industries. His family’s business, Ralph P. Sita, Inc., is a locally owned and operated HVAC contractor with over 42 years of experience, serving the DC, Maryland, and Virginia areas. The company specializes in residential, commercial, and industrial heating, ventilation, and air conditioning services, offering everything from installation and maintenance to custom ductwork and indoor air quality solutions -www.ralphpsita.com.

A former CPA, he spent the last decade as co-founder and co-CEO at Cybrary, a leading platform for cybersecurity and IT training. Cybrary became the largest, most well-known cybersecurity training businesses in the industry under his leadership.

Smart AC Solutions is an opportunity to give back to the HVAC community by providing reliable, actionable information on all things heating and cooling.

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