How to Get Rid of Mildew Smell From AC

mildew smell from ac

When your AC emits a persistent mildew smell, it can quickly turn your once-refreshing space into an unpleasant environment. The presence of mildew odor in your AC system is discomforting and indicative of underlying issues that need to be addressed. 

Fortunately, there are effective methods to eliminate the mildew smell from ACs and restore a fresh and clean atmosphere in your home. By understanding the causes of the odor and implementing the right techniques, you can successfully eliminate the mildew smell from your AC system. 

In this article, we will explore various strategies and steps you can take to banish the unpleasant odor and ensure your AC system operates optimally. And if you need professional help dealing with the smell of mildew from your AC, or if you simply need a maintenance check, Hurliman is always just a call away!

Understanding the Source of the Mildew Smell

When it comes to your air conditioning unit, a mildew smell can quickly turn your cool and refreshing home into an unpleasant environment. Understanding the source of this odor is crucial in addressing the problem and restoring a fresh and comfortable indoor atmosphere. 

There are a few common reasons why your AC may emit a mildew smell, we’ll explore these sources in detail. By better understanding the answer to “Why does my ac smell like mildew”, you’ll be better equipped to tackle the issue head-on and ensure your home remains free from unwanted odors.

Moisture Buildup

When your AC operates, it removes humidity from the air. However, if there is excessive moisture in your system, it can lead to the growth of mold and mildew. This can occur in various components, including the air filter, evaporator coil, and drip pan.

Clogged Condensate Drain Lines

The condensate drain line carries excess moisture away from your AC unit. Over time, it can become clogged with dirt, debris, or algae, creating a breeding ground for mildew and making your AC smell like mildew.

A Dirty Air Filter

A dirty or clogged air filter restricts airflow, causing moisture to accumulate in your AC system. This trapped moisture provides an ideal mold and mildew growth environment, leading to a musty mildew smell from ACs.

Bad Ventilation From The AC

Inadequate ventilation in your home can trap moisture and prevent proper air circulation. This stagnant environment creates favorable conditions for mildew growth and contributes to the unpleasant smell coming from your AC.

Removing the Mildew Smell from Your AC

If you need more time to tackle these tasks yourself, it’s always a good idea to schedule professional maintenance to ensure a thorough cleaning and inspection of your AC system. These steps will help you say goodbye to that pesky mildew smell from ACs and enjoy a fresh and pleasant home environment.

Clean or Replace the Air Filter

The air filter plays a crucial role in trapping dust, debris, and contaminants in your AC system. Over time, these particles can accumulate, creating a breeding ground for mold and mildew. A clean air filter will improve airflow and prevent further mold growth.

Clean the Evaporator Coil

The evaporator coil in your AC unit removes heat and humidity from the air. Over time, it can collect dirt and dust, providing a prime spot for mold and mildew. Turn off your AC and carefully access the evaporator coil. Clean it using a mild detergent and water solution, ensuring you remove any mold or mildew buildup. Allow the coil to dry completely before reassembling.

Clear the Condensate Drain Line

A clogged condensate drain line can contribute to mold and mildew growth, leading to a foul smell. Locate the drain line and use a wet-dry vacuum or a thin brush to clear any blockages. Follow up with a mixture of equal parts water and vinegar, pouring it down the drain line to help kill any remaining bacteria or mold.

Schedule Professional Maintenance

If the mildew smell persists or you need clarification on performing the cleaning yourself, it’s best to seek professional help. An HVAC technician can thoroughly inspect your AC system, identify any underlying issues, and provide a comprehensive cleaning to eliminate the mildew smell. Regular professional maintenance from our team at Hurlima can also help prevent future odor problems and keep your AC running efficiently.

Improve Ventilation

Proper ventilation is essential to prevent moisture buildup and mitigate the growth of mold and mildew. Ensure that your home has adequate ventilation by opening windows, using exhaust fans in bathrooms and kitchens, and maintaining proper airflow throughout your living spaces. Additionally, consider using dehumidifiers to reduce excess moisture in the air.

Some Preventive Measures

Regarding your AC system, prevention is often the key to avoiding unpleasant mildew smells in the future. Preventive measures can help ensure your home remains fresh and comfortable without any unwanted odors. You can minimize the risk of mold and mildew growth in your AC system by implementing a few simple steps. 

From regular maintenance and filter cleaning to maintaining proper ventilation and controlling moisture levels, these preventive measures will go a long way in figuring out why your air conditioner smells like mildew and keeping your AC system odor-free.

  • Regularly clean and replace your air filters as recommended by the manufacturer.
  • Keep your home clean and free from excess moisture by wiping down surfaces, fixing leaks promptly, and addressing any water damage.
  • Maintain proper humidity levels in your home using dehumidifiers or a whole-house humidity control system.
  • Schedule annual professional maintenance to ensure your AC system is in optimal condition and to address any potential issues before they worsen.

By following these steps, you can effectively combat the mildew smell from your AC unit and enjoy a fresh and pleasant indoor environment.


A mildewy smell coming from your AC can indicate underlying issues within the system. This odor is a common factor that contributes to moisture buildup, clogged drain lines, dirty air filters, and inadequate ventilation.

By cleaning or replacing the air filter, cleaning the evaporator coil, clearing the condensate drain line, improving ventilation, and scheduling professional maintenance, you can eliminate the mildew smell and ensure your AC system operates efficiently.

Regular maintenance and preventive measures are key to avoiding future odor problems and keeping your home cool, comfortable, and free from unpleasant smells. Our team at Hurliman Heating & Air Conditioning is just a call away.

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