01/27/2026
NoMoldWNC recently began offering monitoring systems. After our recent cold snap, we got a message from a customer:
“ I’m showing humidity readings of 19% (house) and 21% in crawl space. Seems to be getting too low. Do you think the dehumidifier is turning on / off? Not sure how the settings work (was not provided a manual). Surprised at those low humidity levels with all the moisture falling. Should I be concerned?”
We get this question alot in the winter here in WNC. Here is some info that we like to share with our customers. In the big picture, low humidity is what we want. However, you feel it to be to low due to breathing issues, dry skin, etc., you can always introduce a humidifier during the winter months. Keep in mind that an ideal target for most people is 45%. Also, dehumidifier settings generally should not need to be adjusted due to a cold snap. (Note: a sudden increase in humidity readings, especially in a basement or crawlspace, could indicate a plumbing pipe break, which would need to be addressed immediately. That’s yet another reason to consider crawlspace encapsulation and a sump pump to address those issues.)
Generally speaking, here’s what you need to know about cold weather:
Temperature and Air Capacity: Cold air holds less moisture, so even if it is "saturated" (raining), the actual volume of water v***r is very low compared to summer.
Heating Dries Air: When cold air is brought inside and heated, its capacity to hold water increases, which significantly lowers the relative humidity, making it feel dry.
Rapid Ev***ration/Condensation: In very cold temperatures, water v***r freezes and settles, rather than staying in the air.
Frontal Systems: Rain in winter is often associated with cold fronts that bring in dry air from higher latitudes, decreasing the overall moisture content.
Essentially, winter air is "dry" because of its low temperature, not the absence of rain. Even with rain, the air cannot hold much moisture, leading to low humidity. This creates an environment that is not conducive to mold growth. However, it will not kill living mold that is present. That will tend to come back from a dormant state in warmer weather.
Here in WNC, Spring usually also means more rainfall, water, intrusion, and humidity. Even if we have treated your home for mold growth, controlling the humidity is needed to keep it from returning. That is why we always seek to make that - along with monitoring -part of our comprehensive plan for mold remediation.
