Humidifying Through the Dry Season

What I run

A mold-resistant humidifier through the winter dry-air season, watched on the same Airthings monitor as everything else.

Why winter specifically

Boise is high desert. Cold outdoor air holds very little moisture, and heating it to room temperature drops the relative humidity through the floor — the same air exchange that keeps CO2 down in winter is also what dries the house out. Indoor humidity in the teens is normal here in January, and that is low enough to matter: dry airways filter worse, skin cracks, static builds, and sleep gets worse in ways that are easy to attribute to something else.

Why "mold-resistant" is in the name of the protocol

Because a humidifier is a warm reservoir of standing water with a fan on it, which is a good description of a mold cultivator. The failure mode of humidifying badly is not "it does not work" — it is aerosolizing what grew in the tank into the room you sleep in, which is worse than the dry air it was solving.

So the design of the unit and the discipline of cleaning it are the protocol. The humidity number is the easy part.

The number I aim for

Comfortably inside 30-50% relative humidity. Below 30 is the irritation range; above 60 is where mold and dust mites start, which is why this is a winter-only practice and gets shut off rather than left running out of habit.