How To Treat Mold Hvac System

How To Treat Mold In HVAC System

Finding mold in your home's air conditioning system is something that no one wants to deal with, but it's all too common. When it happens to you, you'll no doubt be wondering how to get rid of mold in the HVAC system.

Regardless of the reason it's found in your ducts, it's something that needs to be dealt with as soon as its discovered due to the potential health effects that it can have on those who live with you. Healthy people may be able to deal with the exposure for a while, but mold spores can wreak havoc on the elderly, pets, those with compromised immune systems, and babies.

Below are some things that you need to know about mold in your HVAC system, what causes it, and how to deal with it.

What Causes Mold In HVAC Ducts

Can mold grow in your HVAC ducts? Sure, if there's plenty of moisture.

Without moisture, mold can't grow anywhere, because wet is one of its basic features. Your duct system serves as a pathway for water vapor to both travel through and settle on when the humidity and temperature are both right. This creates the environment for mold to flourish, especially since your air duct system also carries around plenty of material for the mold to feed on. Mold feeds off of the other debris that flies through your ductwork. This can include anything from pollen, dead skin cells, hair, dust, and many more things.

A good way to help reduce this is having a high level air filter installed into your air return. High end filters aren't cheap, but they stop most pet dander, viruses, germs, mold spores, allergens, odors, and more from getting into your ductwork in the first place. The highest end filter for a normal home air conditioning unit is the Healthy Living 2800 filter by Filtrete. This is great as a preemptive solution, but it's not going to help if you already have a mold problem within your system.

The mold problem that you have could be being caused by not having enough ventilation ducts, air returns, or the HVAC system itself may not have even been set up correctly when your home was built. Another possibility is that a previous homeowner may have done some DIY renovations to the HVAC that weren't done correctly.

How Do I Check My HVAC For Mold

There are a few easy ways that you can check your HVAC system for mold.

The first thing you can do is look into your vents and check for any visible signs of mold either in the vents or on the vent covers. It could look like fuzz, dark (or light!) colored spots, or it could look slimy. We wouldn't advise touching it with your bare hands to find out, though. Some molds can cause severe allergic reactions, so don't touch it without gloves on.

The next thing you can do is trust your sense of smell. If the air coming out of your vents smells musty or like a stinky mildewed towel that's been on the bathroom floor for a few days, you probably have a mold problem there.

Pay attention to your sinuses and whether you have any skin irritations while you're in your home. These are some of the most common signs of mold issues, but mold can also cause other symptoms of illness, including:

  • Memory problems
  • Fatigue
  • Muscle cramps
  • Nerve pain
  • Red eyes
  • Asthma
  • Tremors
  • Night sweats
  • Excessive thirst
  • And more

You should also check the exterior of your air ducts, whether they are in your attic or under your house. If there is condensation on the ducts or if they are sealed improperly, the odds of having a problem is high.

Your air filter that sits in your return (that we mentioned above) could also have mold growing on it, as well, especially if it hasn't been changed in a while.

How Can I Get Rid Of Mold In My HVAC System?

If you don't have an extensive mold problem in your ducts, DIY is an option here. What's considered an extensive problem? 10 square feet, according to the EPA.

The first thing you have to do before you start cleaning is choose a quality disinfectant that's designed to remove mold and is labeled as safe to use in your ductwork. You don't want cleaner fumes being spread all around the house that aren't safe to breathe. As far as DIY cleaners using bleach and such, we would skip those and go straight for a commercial mold disinfectant.

You also shouldn't try to do any of this cleanup without gear that will protect you from not just the mold, but whatever cleaner you decided to choose. You'll need at least an N95 mask, rubber gloves, a protective suit, and safety goggles. A vacuum cleaner also helps, but to be clear about this, when you're using a vacuum cleaner on mold, you'll want to throw your vacuum away afterward because it will be contaminated. It's best to use a wet/dry vac for this.

Supply List

  • Safety goggles
  • Rubber gloves
  • N95 mask
  • Protective suit
  • Vacuum cleaner (dispose of afterward!)
  • Cleaning rags (dispose of afterward!)

If the problem is more than 10 square feet, however, you should call a local mold remediation company to do the cleanup.

Covering the Air Vents

This is step one before you start cleaning. Remove the cover on the wall, floor, or ceiling vents. This is not the larger return air vents that are usually in the wall, but the vents where your heat and cool air comes out into your home. Once you remove the cover, wrap a paper towel over it and put it back so that it prevents air and debris from flowing out. Once you have all of the vents covered and replaced you can move on to the next step.

Turn Off the System

This is done because you don't want to spread mold spores by running the fan at all.

Tapping the Duct Work

Once you have the air going, you will take the end of your brush and go along the duct work in the attic or basement and tap firmly as you proceed. You don't want to bang the duct work hard enough to cause any damage or loosen any connection, but just enough to help loosen the dust and dirt that builds up on the inside walls. Once you have went along banging all of the duct work, then the cleaning begins.

Vacuuming the Vents

Start at one end of your house and go to the other end room by room. Remember, you should have your N95 mask and other protective gear on throughout this entire process. Remove the paper towel from the first vent and throw it away. It will be handy to have a bag or small trash can with you at each vent. Use your brush to go inside the vent piping and loosen any more debris you can reach.

Then take your vacuum hose and reach as far into each side of the vent piping as you can to suck up all of the debris. Once you have cleaned the inside as well as you can, replace the vent cover and go to the next one. Do this until you have cleaned each and every vent as well as you can.

Replacing Filters in the Air Return Registers

Remove the cover for the large air return registers where you filters are located, usually in the wall. Discard the old filters in the trash. Now you can use the vacuum to clean as much of the inside of this vent as you can possible reach. Use the brush to loosen any nearby debris and vacuum it out. Check the vent cover for dirt and dust also. These can be washed in a sink or bathtub if they are very dirty. Make sure the cover is dry and then you can replace it.

Cleaning the Blower Compartment And Return Air Boot

You may also want to clean this part of your unit too. If the furnace is inside your basement, then you can access it from there. If it is outside, then you can access it there. The power to the furnace or central unit needs to be completely off, not just at the thermostat. This is best done by turning the electric breaker off at your fuse box. Once you remove the cover to the unit, you will probably see that dust and debris has built up in there as well. Use your brush to clean this area too, being careful to not touch any wiring. You don't want to loosen or damage anything inside. Then you can vacuum up any debris you see.

If you are handy enough, you can even remove the blower fan assembly and clean that too. However, if you are not that handy or are afraid to disconnect anything electrical, you may want to leave this part to a professional.

It is even possible to take the main truck duct work in the basement or attic apart if you are so inclined. You can reach easier inside to give a more thorough cleaning and then put it back together. Not many homeowners will want to tackle this because it could be easy to damage the duct work or reassemble it incorrectly. Some things really are best left to a professional.

Can Air Samples Detect Mold In HVAC

Absolutely! Home tests are available to test for mold in your hvac ducts and on other surfaces in your home and typically include a laboratory analysis. They're inexpensive (generally under $50) and can give you a clue as to whether you need a remediation specialist to come out to your house and eliminate it.

Can You Spread Black Mold Through HVAC

Any type of mold can easily be spread through your entire home with your HVAC system, because the spores are airborne and move around very easily. If you discover that you have black mold anywhere in your home, you have something to worry about.

Fortunately, stachybotrys isn't often found in homes. Unfortunately, when it is, it can be a huge problem for the health of everyone who lives there, because it can cause symptoms as serious as bleeding of the lungs.

Do HVAC Companies Do Mold Remediation

HVAC companies are not usually licensed mold remediators. For mold removal from HVAC systems that have become infested, you will want a company that is state licensed and certified to deal with the problem.

Some people will say that you can remove the mold yourself, but this isn't advisable. There is a reason that companies must be licensed by the state to do this work; it requires specialized equipment, including respirators and protection suits.

If you believe that you have mold in your HVAC system, you should call a licensed mold remediation contractor to come and check it out immediately.