[bootlooped]

I think it would depend a lot on how much air is moving over it, and the temperature of that air. The surface area of it is pretty large (the whole thing is pretty ginormous also...). The reservoir size is an issue.

I share skepticism about this being used in any serious way. An ultrasonic humidifier is going to be smaller, probably cheaper, and run laps around it in terms of output.

[physicles]

A word of warning: ultrasonic humidifiers used with tap water create high levels of indoor air pollution: https://www.researchgate.net/publication/51859262_Indoor_par...

Disclaimer: I work for a company that makes low-cost air pollution sensors.

[rubatuga]

Debatable whether salt crystals are considered air pollution or simply a problem with the specificity of the PM2.5 definition. Note that this isn't a problem with using distilled water, which is recommended for all humidifiers.

[physicles]

It's not just salt though. In some countries, the tap water isn't safe to drink, so it's probably not safe to breathe.

Also, as another poster pointed out, humidifying a large room in winter requires several liters of water per day. The cost of distilled water would quickly dwarf the cost of the humidifier itself, so other types of humidifiers besides ultrasonic (namely evaporative ones, where the main danger is mold, which distilled water doesn't help you with) are more economical.

[TeMPOraL]

Not to mention ecological. I mean, in Poland, I can't find any sensible source of distilled water other than buying 5L plastic bottles of it. I've briefly looked into devices that could make distilled water, but all that I've found was some industrial-grade hardware that costs more than reasonable for personal use.

[IndrekR]

I have a small under-sink reverse osmosis system for that. Was ~250€. I think it is made in Poland. There are several like that around.

[haarts]

Which company? I'm interested in these sensors.

[physicles]

Kaiterra. Our main consumer product is the Laser Egg.

[tofof]

For a similar surface area I think you could just fill your bathtub to an inch deep and wait for it to evaporate. You'll wait a long time, and your bathtub will get gross, just like this object will.

And with the point being power-free, the air is going to be static or nearly so around the object (or bathtub). If it's supposed to get a boost from moving air from a forced-air furnace, that's cheating -- because in that case you could just install a similarly passive flow-through humidifier on that same furnace and be done with it, save perhaps an annual pad change. Many use no power, just the same "capillary and evaporation" as this - except with actual calculations underlying their specifications.