The moldy ducts scenario is more likely if you have uninsulated ducts or a lot of your ductwork resides in an unconditioned area like your attic.
Mold in furnace humidifier.
If you do not switch on your humidifier for some time and water remains undisturbed in the tank mold will eventually grow and rapidly reproduce.
Mold can grow on the absorbent padding inside the humidifier or on the interior walls.
Plus you will find just increasing your humidity to like 35 40 with your whole house humidifier makes it very comfortable.
Mold can grow on the interior walls.
Wherever there is excessive moisture content mold growth is bound to take place.
The water naturally.
It s cold in your attic so moisture accumulates on the ducts when your humidifier is running.
How do furnace humidifiers work.
It can also live on the absorbent pad inside the humidifier.
And if you are not aware it only takes as little as 24 hours for mold to develop.
Mold loves a moist environment and a humidifier with a reservoir that has stagnant water meets that requirement.
At that level mold is unlikely an issue.
Flow through humidifiers expose the warm air from your furnace to a constant trickle of water.
They re also easier to maintain but they do.
If mold growth goes unchecked the furnace can blow mold spores into your home.
The drain tubes from the humidifier and the ac have mold built up inside.
With humidity that hight and the warm temperatures that natural condition is more likely to produce mold than your 70 degree house in the winter.
This causes a foul musty smell to come from your heat vents.
Turn down the humidistat to make sure the system does not enter a heat cycle while you are servicing it.
Every time your furnace runs it blows mold spores and their musty smell into your home which can not only lead to health issues for your family but can also lead to mold growth in other areas of your home.
The humidifier adds moisture to the air through the furnace ductwork.
Steam humidifers produce either a warm or cool mist and therefore produce the most moisture.
Then mold starts to grow there.
Things needed rubber gloves sponge scrubber or cleaning brush hydrogen peroxide clean cloth chlorine bleach filtered or distilled water.
Mold growth is very dangerous because it causes a lot of health problems.
Annually follow this maintenance procedure to check for scale buildup and eliminate it.
Drain the system of water following the instructions of your particular humidifier model.
Because the interior of a furnace humidifier is a moist environment it is at risk for mold growth.