How to Tell if My HVAC System Has Mold

Mold is a common problem impacting homes. It can grow anytime excess moisture exists. While there are many places where mold is visible, such as on showers, tubs, sinks, walls or windowsills, it can also grow in places that aren’t easy to detect. One place where mold can hide in your home is the ductwork of your HVAC system.

Mold can thrive in HVAC systems due to a variety of reasons, including:

• Oversized air conditioning system – When your air conditioning system is too large for your home, it won’t be able to remove humidity from your home effectively. This additional moisture creates a breeding ground for mold.
• Leaky ductwork – When you have leaks in your ductwork, the resulting moisture will create the perfect conditions for mold growth.
• Running your AC at low temperatures – It’s understandable that you want to keep your home nice and cool during the hot summer months, but if you run your AC at very low temperatures, the super cold air in the system will mix with warmer room air to form moisture inside and around your vents. Over time, this can cause mold to grow in your system.
• Poor ventilation – Clogged air filters or a dirty condenser coil can result in poor ventilation in your HVAC system. This can cause moisture to build up around your air vents, leading to mold growth.

Unfortunately, your HVAC system is a particularly problematic area for mold growth since the spores can spread throughout the house when you run your heat or air conditioning. If anyone in your house has allergies or a history of respiratory conditions, mold in your HVAC system can result in significant health issues.

If you think you have mold in your HVAC system, there are some signs to look for. If you notice any of the following, you should contact a professional mold remediation company at once.

Persistent Musty Odor When Your HVAC System Is Running

Your sense of smell will often clue you into a mold problem in your HVAC system. Mold has a musty, earthy smell that resembles rotting leaves or a damp basement. Often, this smell will be more pronounced when you start running your heat or air conditioning. Next time you run your system, pay attention to the smell coming out of your air vents. If it’s musty, it’s likely that you have mold growing in your ductwork.

The musty smell from moldy ductwork can spread throughout your house, diminishing the overall air quality in your home. It can also exacerbate health issues for anyone who is allergic to mold.

Visible Mold Around the Air Vents

While it’s hard to inspect the inside of your ductwork, you can often detect the presence of mold in your HVAC system by looking around your air vents. Over time, mold spores will settle inside the vents when you run your system, causing discoloration along the outside of the vents. Black, brown or green spots around your vents are generally a clear indicator that you have mold growing inside your ductwork.

Never touch these spots around your vent with your bare hands since this can potentially cause rashes or skin irritation. It’s best to leave it as is and contact a mold remediation professional to handle the problem.

Health Issues

If someone in your home is suffering from unexplained health issues that never seem to go away, it may be an indication that you have mold in your ductwork. Common signs of mold-related health issues include:

• Itchy, watery eyes
• Stuffy or runny nose
• Persistent coughing, sneezing or wheezing
• Dry skin or a scaly, rash-like appearance
• Headaches
• Shortness of breath
• Fatigue
• Nausea
• Difficulty breathing

Moisture Accumulation in the Ductwork

Look inside your vents. If you see excessive moisture – either droplets or standing water – it may be a sign that there’s mold growing in your HVAC system. Mold thrives in dark, damp conditions, so if you see water in the ductwork, there’s a good chance you have a mold issue.