How to fix odors coming from your window air conditioner

Dealing with smells can be a nuisance, but understanding the common causes and how to address them can help restore the fresh, clean air you expect from your window AC. We’re here to help. 

If you find out that you need any replacement parts for your appliance while you’re troubleshooting, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

The troubleshooting information provided in this article may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

Safety precautions

When working on any appliance, remember to keep safety first. Here are some tips to keep in mind: 

• Always power off and unplug your appliance or switch off the circuit breaker before attempting any maintenance or replacement work. This keeps you safe by preventing any risk of injury from electric shock.
• Wear insulated work gloves to protect your hands from sharp metal parts, pinching hazards and debris.
• Take your time and don’t rush while working to prevent accidents and personal injuries.
• Work in a well-lit area so you can clearly see and access the interior parts.
• Clear your workspace of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with bare wet hands. Make sure the work area is completely dry.
• Check your user manual to see if there are specific installation or safety instructions for your part or appliance. 
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause injury.
• Wear safety glasses when working with chemicals, dust or cleaning large debris to prevent injury. 
• If the appliance has recently been used, give it plenty of time for any heating parts to cool down before working on it. 
• Take pictures or make a note of wiring terminals or other connections before disconnecting to prevent any problems with reassembly.
• When working with wires, avoid touching any exposed wires or terminals. If you need to touch a wire, use a non-conductive tool or wear insulating gloves to prevent electrical shock.

Troubleshooting steps

There are several potential causes for an unpleasant odor coming from a window air conditioner unit. Here are some of the common reasons and how to address them:

Cause 1: Mold or mildew growth

Moisture buildup in the unit, often from a clogged drain line or blocked airflow, can lead to the growth of mold and mildew.

Solution: Clean the interior of the unit, including the evaporator coil, drain pan, and any other damp areas, using a mild disinfectant or bleach solution. Ensure the unit is properly draining and there are no blockages.

Cause 2: Dirty air filter

A dirty or clogged air filter can accumulate dust, debris, and even bacterial growth, leading to unpleasant odors.

Solution: Regularly clean or replace the air filter according to the manufacturer’s recommendations.

Cause 3: Decomposing organic matter

Small animals, insects, or other organic matter that may have gotten trapped inside the unit can decompose, resulting in foul odors.

Solution: Thoroughly inspect the interior of the unit and remove any dead or decaying matter. Disinfect the affected areas.

Cause 4: Electrical issues

Overheating of electrical components or wiring within the unit can produce a burning or acrid smell.

Solution: Inspect the electrical system and make any necessary repairs or replacements.

Cause 5: Refrigerant leaks

A refrigerant leak can lead to the emission of a pungent, chemical-like odor.

Solution: Have a qualified HVAC technician inspect the unit, identify and repair any refrigerant leaks, and refill the refrigerant to the proper level.

Additional information

Thank you for reading! We hope this guide helped you get your window air conditioner working again.

If you have any other appliance repair needs or projects, don’t hesitate to explore our other troubleshooting guides and videos. 

If you need replacement parts or some extra help with ordering them, grab your model number and head over to AppliancePartsPros.com, where you can chat with a pro, read our DIY blog and more.

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Keep Reading:

How to Clean Your Air Conditioner the Easy Way

How to troubleshoot & fix common window air conditioner problems  

Window air conditioner isn’t blowing cold air: 8 causes & solutions