Your heating, ventilation, and air conditioning system (HVAC) plays a critical role in making sure your house has the heat, cooling, and humidity control that it needs throughout each distinct season. It also can play an important role in the overall air quality in your house. Failing to change the filter, using an inferior filter, or a filter that isn’t the right size can allow dust allergens and other airborne contaminants spread through your house.

One problem that isn’t always thought of, yet poses a serious threat to your home and health is the possible presence of mold in your HVAC system. Indeed, there are some sources who estimate that at certain times of the year HVAC problems could be causing or contributing to a presence of mold in your home.

Why Is HVAC Mold So Common?

Mold is a type of fungus, which by nature means that it inherently loves high humidity levels and warm temperatures. Most modern HVAC systems create these conditions throughout the heating and cooling process At certain times of the year it means they provide the perfect atmosphere for active mold growth.

It’s also worth keeping in mind that an undersized unit often has to work harder than it’s designed to. This, in turn, produces more condensation than usual which increases your chances of developing an indoor moisture issue.

At the same time, condensation lines with standing water can also be a major problem. It can encourage mold development while also introducing an excessive amount of mold spores to your ventilation system, which blows them throughout your house. By the same token general precipitation, rain and snow can also increase the chances of a mold-friendly environment developing in your HVAC system.

What Are Health Symptoms Of A Mold Problem?

Some individuals have increased tolerance to airborne allergens. While other individuals can potentially have a genetic predisposition to inflammation problems and other issues when there are exposed to airborne contaminants. Especially, things like mold. With some of these, the reaction can be severe and even more long-term health conditions could result.
Some of the most common health symptoms associated with mold contamination in your home is coughing, wheezing, sneezing, shortness of breath, increased problems with respiratory allergies as well as sinus infections, and frequency of respiratory illnesses. This can include developing or suffering from increased problems with asthma, and even pneumonia.

With many of these symptoms, mold doesn’t necessarily need to grow in a specific, visible location. If a mold problem has infested your HVAC system, certain short-term symptoms like coughing, wheezing, and sneezing may start to occur more frequently when the system is actively in use.

Your sense of sight and smell can be the first tools toward identifying the presence of HVAC mold. This might manifest as a visible mold-like substance developing around your air ducts, as well as things like the system’s drip pan or intake vents in a moist area. An active mold infestation also tends to give off a distinctive odor, which is hard to confuse.

How Can I Prevent HVAC Mold?

The size and efficiency of your HVAC system can significantly influence your chances of developing a mold problem. It’s important to have the correct size unit in good working condition. A smaller or outdated system typically struggles to keep up with demands. Especially, when outdoor conditions are already very hot and exceedingly humid.

It’s important to bear in mind that your HVAC system is also responsible for heating as well as cooling and dehumidifying the air in your home. A system that kicks on and off too quickly after reaching its ideal temperature doesn’t have time to thoroughly dehumidify correctly. This could be a problem with an overly large system.

It typically takes around 15 minutes of run time for an HVAC system to start to dehumidify. In ideal conditions, it should run two to three times per hour. When the air conditioning is running in a larger system, water vapor starts to condense on the coils. There needs to be a sufficient amount of condensation on the coil for the water to transfer down to the drip pan below. There also needs to be an adequate amount of water in the pan for it to properly drain away.

The dehumidifying system cannot work properly if the space is not large enough to create the necessary amount of water vapor. In a situation like this, the moisture will simply remain indoors. Unfortunately, humidity levels at 60% or higher offer the ideal conditions for some of the more common types of indoor mold spores.

How Do I Check My Indoor Humidity Levels?

Along with residual moisture and heat, humidity is one of the biggest factors that contribute to the development of mold. Mold spores generally prefer humidity levels over 55 to 60%.

To test the level of humidity in your home, and how it might be impacted by the operation of your HVAC system you can purchase a basic humidity meter. They can often be found in a hardware store for a very reasonable price.

You then turn the meter on and place it over one of your HVAC ducts when the air is blowing out. It will then measure the active amount of humidity passing through your system. If you have a reading that is 55% or higher, then you should strongly consider contacting an HVAC technician. They can calculate the load and the proper size of the unit that you need. Sometimes they can simply identify a fault in your system that may need replacement or repair.

Let them know about any other changes or recent upgrades in other aspects of your home. This might be something like new windows, extra or new insulation, spray foam. In some of these cases, the change in the home may be contributing to the issue as well.

You should also keep an eye out for other aspects of your HVAC system that might be outdated or inadequate. Basic measures that will help include:

  • Keeping Your HVAC system clean by hiring a duct cleaning service
  • Changing air conditioning filters every month
  • Keeping an eye out for any new or existing leaks
  • Checking drip pans and draining away any excess water

Will A Dehumidifier Help?

Humidity levels in your home can fluctuate even if you have the right size system and everything is in good working order. Sometimes severely high humidity from local weather can exceed the dehumidifying capacity of a well-maintained central air conditioning system.

A humidifier is typically not a major investment. Yet it can be incredibly helpful anytime there is excess humidity in your home for any reason.

It can also be very helpful to keep windows and doors closed on days with high humidity days. Not only will this help reduce the influx of humid air, but it can also help your system to work easier.

What Can Be Done To Remove Existing HVAC Mold?

If mold has already managed to infiltrate and establish a presence in your HVAC system, you need to have it remediated as soon as possible. The longer you wait for the more likely you and other members of your family are to experience respiratory and other health issues.

The first step is to stop using your HVAC system. Established mold colonies can spread very quickly. Each time you use your compromised system, a large number of viable mold spores will blow throughout your vents and home.

Can I Attempt To Deal With HVAC Mold Myself?

In a situation where the presence of mold is minor, you might want to try handing mold remediation yourself. However, this can be a little bit more difficult than it seems at first glance.

It’s very important to make every effort to protect yourself, your family members, and pets. Anyone who doesn’t have to be in the building should leave. Then you will need to find a dependable mold cleaning product. Bleach-based products are often insufficient, as they don’t kill the mycelial roots of the mold. Ideally, you want to look for a mold cleaning solution that uses an oxygen-based formula.

When Do I Need To Seek Out Professional Mold Remediation Services?

The truth is, if you are dealing with more than say eight or nine square feet of flat surface that has been affected, you should strongly consider seeking out professional mold remediation. Especially, with something like HVAC mold, which is hard to accurately assess yourself, and the areas needing cleaning will likely require special tools and techniques.