How to Get Rid of Musty Odors in Your HVAC System

Feb 20

If you’ve ever experienced musty smells coming from your HVAC system, you know how unpleasant it can be. These odors are not only bothersome but can also indicate deeper issues within your heating, ventilation, and air conditioning (HVAC) system. Musty smells typically arise from mold or mildew growth, which thrive in damp, warm environments — like the ducts and coils of your HVAC system. Thankfully, there are several ways to eliminate these odors and prevent them from returning. In this blog post, we’ll walk you through the steps you can take to get rid of musty smells in your HVAC system and keep your indoor air fresh and healthy.

A woman smelling a musty odor coming from an HVAC System. Her hand covers her nose as her face contorts into a grimace.

Why Do Musty Odors Appear in Your HVAC System?

Before we dive into solutions, it’s important to understand the root cause of musty smells in your HVAC system. These odors are usually the result of moisture buildup, which creates the perfect breeding ground for mold and mildew. The humidity from air conditioning or condensation can lead to water pooling in certain areas of your HVAC system, particularly in the ducts, evaporator coils, and drain pans. When mold or mildew starts growing in these damp spots, the result is that unpleasant musty odor.

Common causes include:

Dirty Air Filters: Air filters trap dust, dirt, and debris. When these filters become clogged and aren’t changed regularly, they can trap moisture, which encourages mold growth.
Leaking Ductwork: If your ducts have leaks or cracks, they may allow excess moisture to enter the system, creating an ideal environment for mold to develop.
Clogged Condensate Drain: The condensate drain line is responsible for carrying moisture away from your HVAC system. If this line becomes clogged, it can result in water pooling and contributing to the growth of mold or mildew.
High Humidity Levels: Colorado Springs is known for its dry climate, but humidity levels can still rise, especially in the warmer months. If your HVAC system isn’t effectively controlling humidity, this can contribute to musty smells.

Steps to Eliminate Musty Odors from Your HVAC System

Now that we know why these odors occur, let’s take a look at how to get rid of them. Here are some actionable steps you can take to banish the musty smell from your HVAC system.

1. Replace the Air Filters

One of the simplest and most effective ways to address musty odors is by replacing the air filters in your HVAC system. Over time, these filters become clogged with dust, dirt, and moisture, which can lead to mold and mildew growth. Depending on the type of filter, it’s generally recommended to replace them every 1–3 months. This will help improve airflow and prevent mold from taking hold.

2. Clean the Coils and Drain Pan

Your HVAC system’s evaporator coils and condensate drain pan are common places where moisture can accumulate, providing the perfect environment for mold and mildew to grow. If you’re comfortable doing so, you can clean the coils and pan yourself. First, turn off the system and carefully inspect these components. Use a soft brush or cloth to clean them and remove any visible mold or mildew. For a deeper clean, consider using a coil cleaner designed for HVAC systems.

3. Clear the Condensate Drain

If the condensate drain is clogged, water can pool and lead to mold growth. To prevent this, make sure the condensate drain is clear of any blockages. You can use a wet/dry vacuum to suck out any debris or run a mixture of water and vinegar through the line to help break up any buildup. If you're unsure about how to do this, it’s a good idea to call in a professional to inspect and clean the system.

4. Use an HVAC Sanitizer

To help prevent musty odors from returning, consider using an HVAC sanitizer or disinfectant. These products are designed to kill mold, mildew, and bacteria in your system and leave behind a fresh scent. You can apply the sanitizer directly to the coils, ductwork, or other components. Just be sure to follow the manufacturer’s instructions for safe use.

5. Consider a Dehumidifier

If humidity levels are consistently high in your home, adding a dehumidifier to your HVAC system can help. Dehumidifiers reduce moisture in the air, making it harder for mold and mildew to grow. Many modern HVAC systems can integrate a whole-house dehumidifier, which will work alongside your air conditioning to regulate moisture levels more effectively.

6. Schedule Regular HVAC Maintenance

One of the best ways to prevent musty odors from developing in the first place is to schedule regular maintenance for your HVAC system. A professional technician can clean your system, check for leaks, inspect the coils and ducts, and ensure that everything is running efficiently. Regular maintenance can also help detect any issues early on before they become major problems.

Musty odors in your HVAC system can be more than just an inconvenience — they can be a sign of mold or mildew growth, which can affect your indoor air quality and your health. By following the steps outlined in this blog, you can take control of the situation and eliminate those unpleasant smells for good. Regular maintenance and care are essential to keeping your HVAC system running efficiently and odor-free. If you’re in the Colorado Springs area and need help with your HVAC system, American Electrician & Heating is here to assist you. Contact us today to schedule an inspection or service to ensure your home’s air is fresh and clean.