I foolishly bought one off the top of the best-seller list at Amazon a couple years ago. It was like $35 and came with a little card that said "Hey, if you give us a 5 star review and send proof to SHADY_EMAIL_ADDRESS@gmail we'll give you a $25 Amazon gift card!"
It did work reasonably well, but if you failed to clean it and fully dry it out within 6 hours of using it, it would get an INSANE mildew smell.
Amazon of course didn't bother to do anything about the company when I tried to report them, and they seem to have disappeared/rebranded since then
My teakettle is moist for hours, some of my dishes are moist for hours, they don't smell like mildew. I'm in the bone dry south bay in a warm house
My guess is water is getting trapped somewhere in the device's Chinesium crevices, or maybe they found a way to make plastic cheaper by making it susceptible to mold.
Ours just runs until dry. Pretty sure it’s ultrasonic but it’s cheap and there’s never been a smell. Those are the joys of living someplace you really need a humidifier. Water just disappears.
You have to add bleach or humidistat to evaporative ones or keep them running full time. You also have to replace the media once a month or so. The steam ones are better imho.
One of the major issues with humidifier design is that whatever you put into the humidifier gets into the air, which sounds obvious but is an issue. We don't want to use chemicals to keep the paper wick from getting moldy because then we are breathing that. Or with ultrasonic they throw up mineral dust into the air. We end up just buying a lot of paper wicks.
I bought the one he didn't like (the electrode boiler) after watching that video (and his tear-down video [1]). (I have hard water and have had trouble with ultrasonic humidifiers.) It works great! You do have to descale it regularly to keep it going.
Or just get a hot mist humidifier, which does this except:
1. Electronically (ex: you can do this in your bedroom directly, or anywhere you need the warm-mist)
2. With safety measures (its still dangerous, but they minimize the amount of boiling water to minimize the possible harm. Better than an entire pot of boiling water, but still half-a-cup of boiling water can severely burn you still)
3. Probably as cheap as the pot you were using to boil water anyway. Warm mist humidifiers are like $35.
Unless you have a gas stove, in which case prolonged boiling could lead to indoor air quality issues (unless you turn your fan on - but then you're drawing in cold air.
If you have an electric stove, boiling water will be less efficient than evaporating water and letting your heating system make up for the loss in sensible heat unless you have an electric furnace.
