Why Does My House Smell Musty?

Many of us have experienced it: You step inside your Florida home after a hot and humid day, and instead of feeling refreshed, you’re greeted with a musty odor.

With temperatures in the mid-90s across Clearwater and the Tampa Bay area, what you likely smell is mold or mildew that’s accumulated inside your heating and cooling system. And while air fresheners may cover up the odor temporarily, it’s important to address the cause of the smell before more issues arise to your HVAC system or health.

Today, we’ll uncover potential sources and solutions to musty smells and mold growth in your AC system to help your home feel and smell the way it should. 

How Does Mold Grow in My AC?

Mold is part of nature. Outdoors, mold helps break down dead organic matter, like fallen or dead trees. But indoors, mold growth can be dangerous to your health. 

Mold spores grow anywhere moisture is present. It especially thrives with the addition of warm air, a dark environment, and dust and debris—so your HVAC system can be an ideal breeding ground for mold, mildew, and bacteria. That’s why regular AC maintenance is so important. 

According to the Environmental Protection Agency, if you suspect that your HVAC system may be contaminated with mold, act quickly. Don’t run your AC system because it can potentially spread even more mold throughout your home. Instead, reach out to a certified AC professional for assistance in cleaning your system.  

Contact Air Care to schedule an appointment today.

How Do I Remove Mold from My AC?

Since your HVAC system can be a common place for mold to grow, let’s explore the cause and solution for each potential source of musty smells in your home. 

Source 1: Evaporator Coils 

Evaporator coils work in tandem with your system’s refrigerant (freon) to cool the air in your home. When too much moisture builds up on the coils, bacteria can grow and cause a strong odor. Some customers describe the smell similar to that of dirty socks. 

The reality is that evaporator coils have the right environment for mold to grow:  

    • The coils are located in a dark area inside your AC unit.
    • Warm air constantly blows over the coils before cooling down.
    • Moisture forms on the coils.
    • Dust and debris often get caught in the coils.

The best ways to prevent the growth of mold on your evaporator coils is to: 

    1. Have your coils cleaned regularly, and
    2. Invest in a UV light purification system.

At Air Care, our AC technicians will properly inspect your coils during each tune-up and maintenance visit. If bacteria is present, they will properly remove, clean, and reinstall your evaporator coils in your unit, making it safe and easy to breathe again.  

We also recommend installing a UV light purification system in your AC unit, which fights against germs, mold, allergens, and odors inside your HVAC system and home. UV light can extend your system’s life and make it more efficient, while also cleaning your indoor air from harmful pollution.  

Contact our team at Air Care today to schedule an AC tune-up and coil cleaning and inquire about the UV light purification system. 

Source 2Clogged Condensate Drain 

When condensation forms on the evaporator coil, it empties into the AC drain pan and exits out the condensate drain line. However, if your condensate drain gets clogged, then unwanted water can back up into your drain pan—and now mold has everything it needs to grow and thrive. 

To avoid excessive mold, mildew, and unwanted smells in your home, be sure to inspect your AC condensate drain regularly for buildup or blockage. If your condensate drain line has a minor clog, you can consider cleaning it on your own. (Read about it in another blog post, 4 Easy DIY AC Maintenance And Repairs For Your Florida Home.)  

For more difficult clogs, contact our team at Air Care.  

Source 3Dirty Air Filter 

Just like every other living organism, mold spores live on food. And inside your home, mold’s favorite food is dirt, dust, and debris. 

The good news is, your air filters stop this “food” from entering your central heating and cooling system. However, you must check and change your AC filters often to ensure your HVAC system stays free from mold and mildew—which can lead to musty smells and harmful bacteria breeding in your home. 

As a reminder, be sure to check your air filter at least every 30 days, and contact Air Care if you have questions.

Source 4Disconnected or Leaky Air Ducts 

We like to think of air ducts as a series of roads and highways, getting your conditioned air where it needs to go with the support of your central HVAC system. If part of your ductwork becomes disconnected and leaks, conditioned air meant for indoor living spaces could be delivered elsewhere—like your attic or a crawlspace. Your ducts can also pull in warm air, dirt, and debris into your system, contaminating your ductwork and making a perfect environment for mold to grow. 

How can you tell if you have leaky ducts in your home? Ask yourself the following questions: 

    • Is one room cooler or warmer than others?
    • Do certain rooms seem stuffy or uncomfortable?
    • Are your air filters constantly dirty?
    • Do you spend too much time dusting a particular room or area of the house?
    • Are there visible signs of leaks, disconnection, or deterioration in your ductwork? 

If you answered yes to any of the questions above, call your AC professionals at Air Care to have your AC ductwork inspected and seal off any leaks to prevent mold growth. 

Source 5Unused AC Units 

Mold can also grow in your AC system if it’s left unused for an extended period of time. That’s because dust and debris will collect inside and outside the unit when it’s not running, and with the right amount of heat and humidity, mold spores can grow and feed on the dust particles in your HVAC system. 

If you own a home or condo in the Clearwater area and use it for only part of the year (ex: the winter months), you may consider hiring a cleaning company or asking someone you know to occasionally turn on your AC unit while you’re away. You can also invest in a smart/programmable thermostat and preset your system to circulate regularly to prevent mold from growing. 

Contact Air Care today if you’ve left your HVAC system unattended and need AC maintenance, replacement, or repair.

How Do I Remove Mold from My Window Unit?

Similar to central HVAC systems, window units can also commonly collect and breed mold. Because of the size of the unit and job, it’s tempting to attempt mold removal on your own—but keep in mind, the proper safety practices and tools are needed to get the job done.

Click here to learn How to Clean Mold from Your Window Air Conditioner, compliments of HVAC.com. Need professional help? Contact Air Care today. 

Turn to Your Clearwater AC Professionals for Mold Removal 

If you suspect mold in your central HVAC system, window unit, or ductwork, call our professionals at Air Care for help. Our AC technicians are licensed and trained to handle the removal of mold and mildew from your AC unit in your Florida home. 

We also recommend a bi-annual tune-up and service on all HVAC systems and brands. During each visit, we’ll inspect your system to ensure it’s running properly and help prevent mold growth inside your equipment. 

“For seven years, Air Care has come twice a year. They are great–if you need service, don’t use anyone else. I recommend this company to everyone who needs AC repairs.” — Gail R. of Palm Harbor 

Contact Air Care for clean and cool air today. 


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