6 Reasons Your Air Conditioner Smells Musty (and What to Do About It!)

Is there anything better than that first day of summer when you turn your air conditioner on? You hit the power-on button and embrace the feeling of ice-cold air to help cool you off.

However, instead of being met with cold air, you’re met with a musty-smelling air conditioner. Though this may seem like a mind inconvenience, you’ll need to act fast as this smell can indicate a more severe problem.

If your air conditioner smells musty and you’re not sure why, keep reading for some of the most common causes and how to remedy them.

  1. Mold and Mildew Growth

One of the most common AC smells is must, caused by a buildup of mold and mildew in the unit. While you may see mold and mildew as a minor inconvenience due to the smell, they can cause serious health issues.

Instead of settling for breathing in mold, you’ll need to clean and sanitize the unit. However, it can be messy and challenging to get rid of buildup. When cleaning, ensure you’re in a well-ventilated area with gloves and a facemask.

In order to prevent mold and mildew from growing in the future, ensure your units are properly fitted to deter rain and moisture from entering your air conditioner. Similarly, ensuring that your system has the proper drainage is essential.

  1. Dirt and Dust

Much like mold and mildew, a buildup of dust and dirt in your unit can cause your air conditioner to emit a musty smell. This is due to the amount of dirt in the system and filters.

If your filters are caked in dirt and dust, this can lead to a musty odor, but you may also notice that your unit isn’t working as well as it should be.

This is because the airflow has to break through layers of dust and dirt to cool your home, so your system won’t be as efficient as it should be.

As the air tries to push through the dirty filter, it can circulate a dirty, musty smell throughout your home. Cleaning your filters out can help remedy the issue.

  1. Clogged Drain Lines

Every air conditioning unit comes fully equipped with a drain line. This piece plays a crucial role in draining your system of condensation that occurs within the unit as a result of evaporation from coils.

When your drain lines are clogged, it can cause an excess of condensation in your unit, as the moisture has nowhere to go. This can lead to condensation in your unit, causing mold and mildew to grow.

However, you can clear out your drain line as a fix for the issue. Adding vinegar to your drain line can help break up clogs in the line, flushing out the buildup of dirt and grime. You may need to repeat the process a few times until the drain is fully cleared.

To prevent this from occurring, regularly flushing your drain line will remove any dirt particles before they become a significant issue in your home. This can help remedy a musty-smelling air conditioner.

However, if the problem persists, you may need to contact an AC repair service for further assistance.

  1. Full Drain Pan

Much like a clogged drain line, the pan that collects moisture from your AC unit can become distorted and dirty. When the collection tray breaks or becomes clogged with dirty, standing water, leading to mold and mildew. This can cause the musty smell to emit from your unit.

To clean your drain pan, you’ll need to dispose of the dirty water safely. Then, you’ll want to use bleach to sanitize the surface, killing any mold or bacteria that has grown.

If your drain pan is rusted, cracked, or distorted, you may be better off investing in a replacement. You’ll also want to check your unit for any damage, as the pan shouldn’t be full of water to begin with.

  1. Frozen Evaporator Coils

When your air conditioner isn’t functioning properly, this can cause your evaporator coils to freeze over. A lack of airflow restricts where the cold air is going, which can track the coolness in your system, causing the coils to freeze.

When these coils that absorb heat are frozen, the moisture that builds up can house bacteria, as these parts are in a hidden area of your unit, meaning they can end up with dirt, mold, and bacteria caking them.

To fix the issue, you’ll need to turn off your unit to allow the coils to thaw. You’ll also want to check to ensure that they aren’t dirty. Because a system malfunction can cause the coils to freeze, you’ll need to check the rest of the unit to prevent them from refreezing.

  1. The Unit Is Too Big

If the unit in your home is too big for the space, it can lead to a musty smell. This is because a unit that’s too large doesn’t have time to properly dehumidify the air.

Large units pull in more air to cool your home quickly. However, if the system is the wrong size for your space, it can cool too fast, thus releasing a musty smell.

If you’ve checked every area of your air conditioner and haven’t found any standing water, the buildup of moisture, dirt, or mold, could be the issue causing a musty smell coming from your AC.

Air Conditioner Smells Musty? Try These Fixes

Your bad-smelling AC might seem like a minor inconvenience. However, it can indicate a major issue! If you’ve been wondering, “why does my AC smell musty?” this guide can help you get to the root.

Ensuring your unit is working correctly is essential to staying safe and healthy during the summer.

If you found this guide to why your air conditioner smells musty informative, you’ll want to check out the rest of our website. There, you can find more great home and lifestyle tips and tricks.