Whole House Humidifier & Mold – Signs + How to Control It

Mold is a great concern in homes with a whole house humidifier. The fungi thrive in moist humid conditions occasioned by the use of a humidifier. By now you know that mold is a serious health hazard. Let’s look at how a whole house humidifier may cause mold, signs, and how to control it.

A whole-house humidifier produces a large amount of moisture that can condense on surfaces or in the HVAC system to attract the growth of mold. This can be accelerated by low temperatures or dust and dirt that act as food for mold in the furnace, ductwork or other surfaces in a home.

Can a whole-house humidifier cause mold?

A whole-house humidifier is usually installed on the ductwork near the furnace. It is also connected to a water supply so that when the furnace is set on to blow warm air in a home the central humidifier also runs to add moisture to the supplied air. This creates a comfortable indoor climate during cold weather.

Although modern whole-house humidifiers automatically keep humidity levels in a safe range of 30%-50%, a drop in indoor temperature can lead to moisture condensing on surfaces when they get cold. This is likely to attract the growth of mold on walls, ceilings, furniture, and other areas.

Further, in most homes, ductwork is installed in unconditioned areas like the attic. These areas remain cold even when the rest of the house is getting heated. This makes moisture condense on the ducts, a scenario that will attract the growth of mold. This also happens for uninsulated ductwork.

Mold can also grow inside the heating, venting and air conditioning system if the indoor air handler or furnace is extremely dirty with dust. Adding moisture to dust and darkness forms a haven for mold. This becomes more dangerous as the air you will be breathing will be containing mold spores.

Whole house humidifier mold signs

Sometimes it’s not easy to tell with your eyes that mold is growing in your HVAC system. Whole house humidifiers are not like portable humidifiers where you can open a few areas to check for mold. These are perfectly sealed devices that need an HVAC expert to open the covers and check if there is mold.

The following are signs of a whole-house humidifier mold:

  • Musty odor – You may be lucky to detect a musty smell in your home during air conditioning. A stale smell signals some decaying which is the primary function of mold.
  • Allergic reactions – For some households, allergic reactions like respiratory irritation can point to the presence of mold in the air. Mold produces spores, which when inhaled causes coughing, sneezing, runny nose, watery eyes, and more.
  • Powdery substance on surfaces – Mold growing on surfaces like walls, ceilings, and furniture will appear as a black, pink, or white powdery substance.
  • Condensation on glass windows – Glass windows get colder and any excess moisture in the air is likely to condense on them. This should be alarming when you are running a central humidifier.
  • Peeling surfaces – Moisture will cause peeling of paint, wallpaper, and other coatings on surfaces. If this is happening in your home then you should get prepared to deal with mold in your house.

How to Control Whole House Humidifier Mold

Mold is helpful in nature as it helps in decomposing organic matter but is very harmful to humans and pets. If you have been running your central humidifiers and detect any sign of mold in your home or HVAC system, then here is what to do.

You will need to contact an HVAC expert and inform them about the possibility of mold in your home. If the expert inspects and confirms the presence of mold, then you have to vacate your residence for mold remediation. It will not be safe to be around when cleaning, removal, and treatment of mold are done.

What the HVAC expert will do

  1. The expert will turn off the power and open the humidifier and furnace covers to access their innards. In conjunction with air duct cleaning professionals, they will begin the cleaning process.
  2. After wearing protective equipment, the professionals will use an EPA-registered disinfectant formulated for HVAC use to clean the affected non-porous surfaces.
  3. In the furnace, they will target caked dust and dirt on the blower fan, evaporator coil, motor, and plenum. These parts may also need to be changed if their recommended lifetime has lapsed for the proper functioning of the furnace.
  4. They will also clean the whole ductwork to remove any available mold, moisture and dust
  5. Finally, they will change the evaporator pad in the whole house’s humidifier. This part needs to be changed yearly during the servicing of a whole-house humidifier.

Killing mold on other home surfaces

Once every part in the humidifier, furnace, and HVAC system is free of mold, treatment on the rest of the home surfaces will follow. This includes affected walls, ceilings, furniture and other non-porous surfaces. Bleach solution, distilled white vinegar or a commercial mold cleaner will effectively kill mold.

The process of killing mold with bleach is straightforward. You simply mix 1 cub of bleach with 1 gallon of water and spray the solution on the surface with mold. After about one hour the mold will be dead and you can scrub it off, rinse and let the surface dry completely.

You may also use distilled white vinegar to kill mold. Simply pour the solution in full strength in the spray bottle and directly apply on the mold. After 30 minutes scrub the moldy surface using a wash brush then rinse the surface with warm water.

Commercial mold cleaners are also effective at cleaning the household mold. They are available at any nearby cleaning store. These products should be used as directed by their manufacturers. Carefully read and follow label instructions before using.

Final Thought

Whole house humidifiers are great at maintaining comfortable indoor humidity but they come with the dangers of mold. This will always be a problem if you don’t clean and operate your HVAC system as required. Mold is harmful to your health and you should not hesitate to take action when you suspect them in your home or HVAC system.

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