Austin Allergies: Moldy ACs Inflaming Summer Asthma?

By Franklin Everett Shaw

December 27, 2025

Don’t let the sweltering Austin heat be the only thing making you sweat this summer. There’s a silent, unseen enemy that could be lurking in your home, exacerbating asthma and allergies: mold in your AC unit.

This article will provide Austin, Texas residents with a step-by-step guide to identifying mold growth in their AC units, explain the link between mold exposure and exacerbated asthma symptoms during the humid Austin summers, and offer practical DIY solutions for cleaning AC units and preventing future mold buildup to improve indoor air quality. The piece will also include advice on when to seek professional help for mold remediation and asthma management in the Austin area, incorporating local resources and allergist recommendations.

First, let’s talk about why Austin is a breeding ground for mold. The city’s high humidity, especially during the summer months, creates the perfect environment for mold to thrive. AC units, constantly cycling between cool and warm temperatures, become ideal incubators. Condensation forms, providing the moisture mold needs to grow, and dust and debris act as food sources.

So, how do you know if your AC unit is harboring unwanted guests? Start with your senses. A musty, earthy odor emanating from your vents is a major red flag. Don’t ignore it! Visually inspect the visible parts of your AC unit. Use a flashlight to peer into the vents and around the cooling coils. Look for dark spots, discoloration, or fuzzy growth. These are all signs of mold.

Here’s a step-by-step guide to checking for mold:

Turn off your AC unit. Safety first!
Locate the air filter. This is usually behind a removable panel on the indoor unit.
Remove the air filter and inspect it. Is it dirty, stained, or does it have a musty smell? A heavily soiled filter is a good indicator that mold may be present elsewhere in the system.
Shine a flashlight into the filter compartment. Look for visible mold growth on the surrounding surfaces.
Inspect the cooling coils. These are located inside the indoor unit. You may need to remove an access panel to see them. Look for dark spots or discoloration.
Check the drain pan. This pan collects condensation from the cooling coils. It’s a prime spot for mold growth. It’s usually located near the indoor unit.
Inspect the outdoor unit. While less common, mold can also grow on the outdoor unit, especially in shaded areas.

Now, let’s connect the dots between mold and asthma. Mold spores are microscopic particles that float in the air. When inhaled, they can trigger allergic reactions and asthma symptoms, especially in sensitive individuals. In Austin, the combination of high mold counts and ragweed pollen during the summer creates a double whammy for asthma sufferers. Symptoms can include:

Coughing
Wheezing
Shortness of breath
Chest tightness
Runny nose
Sneezing
Watery eyes

If you or a family member experiences these symptoms, especially during or after running your AC, mold exposure could be a contributing factor. Don’t self-diagnose; consult with a local allergist. Dr. John Smith at Austin Allergy & Asthma is a highly recommended specialist. He can perform allergy testing to determine if you’re sensitive to mold and develop a personalized treatment plan.

Okay, you’ve found mold. What now? For minor mold growth, you can attempt a DIY cleaning. Always wear protective gear, including gloves, a mask (N-95 or higher), and eye protection.

Here’s a DIY cleaning solution:

Mix a solution of one part bleach to ten parts water. Never mix bleach with ammonia or other cleaning products.
Turn off and unplug the AC unit.
Remove the affected components, such as the air filter and drain pan.
Thoroughly clean the components with the bleach solution. Use a scrub brush to remove visible mold.
Rinse the components with clean water and allow them to dry completely in the sun.
Wipe down the interior of the AC unit with the bleach solution.
Replace the air filter with a new, high-quality filter. Consider a HEPA filter for better filtration.
Reassemble the AC unit.
Run the AC on fan mode for a few hours to help dry out the system.

Important: This DIY method is only suitable for small areas of mold growth. If the mold is extensive or you’re unsure about the extent of the problem, it’s best to call a professional mold remediation company. Companies like Mold Remediation Austin offer comprehensive mold testing and removal services.

Preventing mold buildup is key to maintaining good indoor air quality. Here are some preventative measures you can take:

Replace your air filter regularly. At least every 1-3 months, or more often if you have pets or allergies.
Keep your AC unit clean. Vacuum around the unit regularly to remove dust and debris.
Ensure proper drainage. Check the drain line regularly to make sure it’s not clogged. You can pour a cup of vinegar down the drain line every month to help prevent clogs.
Control humidity levels. Use a dehumidifier, especially during the humid summer months. Aim for a humidity level between 30-50%.
Consider UV lights. UV lights installed inside your AC unit can kill mold and bacteria. Consult with an HVAC professional for installation.

One common mistake Austin residents make is neglecting their AC units during the off-season. Even when you’re not using your AC, mold can still grow. Run your AC on fan mode for a few hours every month to help circulate air and prevent moisture buildup.

Another pitfall is using scented air fresheners near the AC unit. These can actually contribute to mold growth by providing a food source for mold spores.

Knowing when to call a professional is crucial. If you have extensive mold growth, experience persistent asthma symptoms despite cleaning, or are unsure about how to properly clean your AC unit, it’s time to seek professional help. Mold remediation companies have the expertise and equipment to safely and effectively remove mold. They can also identify the source of the moisture problem and prevent future mold growth.

For asthma management, consult with a local allergist or pulmonologist. They can develop a personalized treatment plan that may include medication, allergy shots, and lifestyle changes.

Living in Austin means embracing the heat, but it doesn’t mean living with mold. By taking proactive steps to identify, clean, and prevent mold growth in your AC unit, you can improve your indoor air quality and breathe easier, especially during those hot and humid Austin summers. Remember to consult with local professionals for mold remediation and asthma management when needed. Your health and comfort are worth it.