HVAC Mold: How to Keep Your System Mold-Free

HVAC Mold

What Causes HVAC Mold?

This time of year, we have many new clients whose problem with mold generates from their HVAC not running properly. We want to make sure you are aware of this issue so that you can safeguard your home. It has been said that more than 50% of mold issues have been caused by HVAC systems. But why is this HVAC mold so common?

First of all, it wants to have a party every time it encounters an area with high humidity levels and warm temperatures. These conditions are created during the heating and cooling of HVAC systems. That makes both over-sized and under-sized systems the perfect atmosphere for active growth. Improperly sized unit has to work harder than it should. This creates more condensation than usual and can easily cause a moisture issue. Condensation lines with standing water is a big problem. Not only will mold grow here, but an excessive amount of spores will be blown throughout your home every time your HVAC system turns on. Rain, snow and other precipitating substances can also create a mold-friendly environment in HVAC systems.

HVAC Mold Symptoms

  • Health Symptoms – Health symptoms of HVAC mold could be the same health symptoms that you would experience if the mold grows anywhere else in your home. The most common of these health symptoms includes coughing, wheezing, allergies, asthma, sneezing, pneumonia, sinus infections and respiratory illness. While these symptoms do not require a specified location of growth in order to appear, if the mold problem is in your HVAC system, symptoms such as coughing and wheezing may appear more prevelently while the system is in use.
  • Sensory Symptoms – The two senses can help identify HVAC mold is sight and smell. If you can see a mold-like substance growing around your air ducts, drip pan or intake vents, there is likely a mold problem there. Also, if the smell of mold is most prevalent when the system is in use, there is likely a mold problem.

How to Prevent HVAC Mold

  1. Most importantly, make sure that your HVAC system is the correct size. Many people believe that investing in a larger system will work since the system won’t have to work as hard. This belief is true. In fact, it’s so true that the HVAC system doesn’t only have an easier job, but it gets to only do half of it’s job. The unit does a great job at heating and cooling. It cools down the property and when the ideal temperature is reached, the system shuts off. It does it quickly, but maybe too quickly.

    The problem is that an HVAC system has two jobs: heating/cooling and dehumidifying. The system kicks on and off so quickly since it reaches it’s ideal temperature in a short amount of time, that it doesn’t have time to dehumidify correctly. It takes a minimum of 15 minutes run time for a unit to start to dehumidify and under normal conditions, an HVAC system runs 2-3 cycles per hour. While running the air conditioning in a larger system, water vapor condenses on coils. There has to be enough of condensation on the coil for the water to drip into the pan below. Also, there has to be an adequate amount of water in the pan for it drain outdoors. This dehumidifying system won’t work if the property space is not large enough to create the correct amount of water vapor. Instead, the moisture will remain indoors. Humidity levels at 60% or higher provide perfect conditions for growth of common species of mold that often looks like dust.

    Undersized systems will also create a humidity issue. These are usually the hard workers of the HVAC world. They are overworked and have too much on their plate to keep the property cool/hot and dehumidified. Not only will temperature levels almost never reach the ideal temperature, but the indoor environment is likely to become humid. This doesn’t only threaten the air conditioning system with mold, but the entire property.

    How to Check Your Humidity Levels

    Place a humidity meter and over your HVAC duct to measure the humidity levels of the air blowing out. Humidity readers can be purchased at most home improvement retail stores. If the humidity reads 55-60%, you need to call an HVAC expert. An expert can calculate load and the proper size unit that you should install in your home. Be sure to tell the expert if you have added any changes that would create more efficiency, such as new windows, extra or new insulation, spray foam, etc.

  2. Other Prevention Methods

  3. Keep your HVAC system clean.
    • Change air conditioning filters monthly
    • Check for leaks regularly
    • Drain any excess water and clean pans regularly
    • Clean air ducts regularly
  4. Invest in a dehumidifier. Use a dehumidifier anytime there is excess humidity in your home for any reason. Humidity levels can rise due to issues including floods, plumbing issues, humid outdoor conditions, etc.
  5. Keep windows and doors closed during humid days. Keeping humidity outdoors can not only keep the indoor humidity levels lower, but it can allow your system to work easier, resulting in less condensation and a longer lifetime for your system.
  6. Check your drip tray regularly. Standing water in drip trays can cause active growth.
  7. Have an HVAC company come out to inspect and clean your system regularly.
  8. Do not constantly run your fan. It is common that HVAC technicians and installers will recommend that you run fan constantly to circulate the air. Initially, this seems good, but in reality it will create extra humidity in your home and fuel mold growth.

Mold Removal

If you already have HVAC mold, what do you do? The first thing that you need to do is to STOP using your system. HVAC mold spreads fast! Every time you use your moldy system, mold spores will blow throughout your ventilation system in huge amounts and could begin growing in other areas of your home or business. Once you stop using the HVAC system, below is how you can go about the HVAC mold removal process.

DIY Mold Removal

If you’re dealing with a small amount of mold (less than nine square feet), you can try a DIY removal process. The first thing that you will need to do is protect yourself and your family or employees. After protecting everyone, you will need to find a dependable mold cleaning product that does not use bleach and follow the instructions given by the manufacturer. We go over the details for how to do this, and why not to use bleach on our What is Mold page.

Professional Mold Removal

If you are dealing with more than nine square feet of contamination, or if you just don’t want to clean it yourself, you will need to contact a company that can help with your HVAC mold remediation.

With high humidity levels throughout the property and excess moisture in your HVAC system, Aspergillus could grow. Aspergillus is on of most common mold species and looks similar to dust and floats around like dandelions. When a person inhales an excessive amount of these spores, it causes a health condition known as Aspergillosis, which physicians often overlook. Learn about Aspergillosis here.

If you still have HVAC mold questions, feel free to give us a call at 317.837.6665 or send us a message.