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Convincing water to just evaporate on its own was always going to be a bit tricky. The energy needs to come from somewhere so your best bet is to just get it into contact with enough dry air and hope for the best.

Besides if you're trying to restore humidity lost by heating your room then pure energy wise there's not that much difference in evaporating the required amount of water using ambient heat or evaporating the required amount of water using a different energy source. The only thing you'll achieve by using ambient heat is that your room will cool by the amount of heat required to evaporate the water (a good thing in the summer, somewhat pointless if your aim was to make a room both warm and comfortably humid).

Fundamental thermodynamics will probably mean the 'wait and see' approach is more efficient in the end, but it makes no promises on efficacy. The difference in efficiency probably lies in the fact that you can heat a room with an efficiency >100% if done right, if you haven't managed that yet it probably doesn't really matter which way you humidify the room.

Even without a system that has >100% efficiency (i.e. a heat pump), home heating systems often use a source of heat that is significantly less expensive per watt than electricity. (For example, natural gas.)

Well that depends on what you're optimizing for, but yes.

Gas-fired humidifiers exist, though I'm not sure if you can get small ones easily.

In places with hot dry summers, the evaporative approach is vastly more efficient than boiling water.

As a resident of a place with hot dry summer, I can confirm that the last thing I want to do is to add to the heat with boiling water.

The evaporative approach will actually manage to do something that's generally impossible as it will actually cool down the air. Obviously this is the superior method to deal with hot dry air.

The use-case described in the article however:

>The east coast’s dry winter air, parched further by the radiators that can barely keep up with the chill, causes great discomfort to me and millions

suggests they're trying to heat the space they're in. At which point you'll need to recover any heat lost by evaporation anyway.

So, there are some unpowered options, none of which are as efficient individually as a powered humidifier, but may work in tandom:

1) Plants - they release the water you put into them into the air, as part of how they pull water up from the ground to the leaves.

2) Open Water - Aquariums, fountains, etc.

3) Humidifying balls - basically rough ceramic balls which sucks water up into them, and the water naturally evaporates. Slow, though, and if your water has any impurities they will accumulate on the surface.

4) Humans - we breathe out a lot of water, and if your house is well enough sealed, you'll actually have to de-humidify, even if the air outside is dry. Costly, though.

There is better way to humidify which is to just have cold temperature evaporation. It is slower and you need bigger machine for the same volume, but it requires very little energy and the only real electronics is a fan that moves air.

I got rid of all mist humidifiers because of residue, noise and some health concerns (no, I am not feeling safe inhaling those fine particles) and I am happy for it.

Most importantly, it doesn't get things wet and it is safe to just leave it 24h.

The Honeywell in question is this type-- it calls itself a "cool mist" humidifier, but it's an evaporative humidifier: basically all there is to the thing is a water tank, a wick, and a fan to move air over the wick.

The slag issue can be solved by using demineralized water, and reverse osmosis water filter, which remove almost all minerals, can be had for pretty cheap these days.

People say "pretty cheap", but a lot of reverse-osmosis filters I've seen are ~$150 to $450.

Also consider: it takes ~4 gallons of water to make 1-gallon of reverse-osmosis water. All water-purification methods have their own issues.

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If you plan to make distilled water (aka: boil water to remove impurities)... that's basically what a warm-mist boiling-type humidifier does _anyway_.

All good water-purification methods either take up a ton of water (ie: reverse osmosis) or a ton of energy (ie: distilled).

RO doesn’t fundamentally need much energy or all that much waste. This system claims to be much less wasteful by recovering pressure using a “permeate pump”:

https://www.theperfectwater.com/home-master-hydroperfection-...

I personally think an evaporative humidifier is the way to go, as long as you are okay with the evaporator getting gross over time.

I have an under-sink RO/DI system, the whole system was about $200. It's a great investment for a place with hard water. I use it to get demineralized water for my house plants, fish tank, and drinking.

I use the RODI for expensive steam appliances like my Wagner, but I don't use RODI for regular old vegetable steamers or humidifiers. It's just not worth it. The scale buildup isn't a big deal and it's very easy to dissolve with an acid or just brush off.

For people with Ultrasonic humidifiers (which spray the scale across the room as white-dust), it is a much bigger pain to clean that up with regular dusting.

For warm-air humidifiers (aka: boiling water), where all the scale is concentrated onto the heating element: yeah... no big deal. A cup of cheap 5% vinegar and 20-minutes of waiting is all you need to clean that off.

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I think if you have RO water, it probably makes sense to use an ultrasonic humidifier.

> 1. Warm Mist humidifiers work by boiling water. This has the downside of... well... boiling hot water hanging around the area. But otherwise, these are the simplest and are only ~$20 or $30.

Or $0 if you have a pot, a stove, and a tap.

You're going to move your stove to your bedroom and leave it on while you sleep?

You're paying $20 to $30 for safety auto-shutoff features so that you can leave these things on all night long, and not have to worry about fumes, fire, or a myriad of other issues.

Yeah, its basically equivalent to a pot of boiling water + a stove. But... being able to move it to the locations you need (and safety features to boot) is the big advantage.

Depending on the size of your apartment and the amount of air exchange, running it for 20 min before you go to bed may be perfectly sufficient until morning.

But yeah, I see the point. Just wanted to point out this alternative - when it comes to humidifying through boiling, it's a matter of dumping energy into water, and your stove is excellent at doing that quickly. With a regular humidifier, you may need to wait hours until you get the humidity where you want to have it, a stove can be much faster.

I just put up with the dryness and static.

Boneco makes ultrasonics I like but the humidity on the other hand makes mold more viable. Plus you have to buy filters and cleaners.

Do any humidifiers use UV to disinfect?

The Honeywell one does... probably has some benefit, but doesn't solve the issue.

Put some 3% H202 into a spray bottle. Then spray the humidifier once a week all over to disinfect.

Proper Bleach (Sodium hypochlorite) is probably cheaper, but there's a major convenience factor to just spraying H2O2, and Hydrogen Peroxide is pretty cheap as it is ($2 for 1-liter).

Its not so much that the disinfection was hard to do in my case... Its that it became somewhat of a hassle. Warm Air is nice since it auto-disinfects itself with boiling water. I still disinfect manually, but just once-a-week instead of every day.