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Comment by JohnJamesRambo | Hacker News Reader

When I finally got a hygrometer I was amazed at how useless the powered one gallon air humidifiers are. They often can’t raise the humidity percent a single point with the hygrometer right by it in my rooms.

If you want to really humidify a room it takes a big industrial sized unit. They had them in the rooms in our Colorado Airbnb cabin and they were totally necessary in the dry mountain air if you didn’t want to wake up in pain from dried out mucus membranes. Very loud and used many gallons of water in a single night.

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When I was a kid in the eighties we had these huge “console” humidifiers that held maybe 15 gallons and had a rotating belt and a big fan. Seems like they stopped making these in the nineties in favor of the useless tiny things.

My grandpa used to have the exact same thing.

You can still buy smaller versions of, they are called 'evaporative humidifiers' and use a paper element with a fan. They are slower to adjust humidity but leave zero haze.

I have a rather small Honeywell cool mist that works well. I use it in our bedrooms and have taken the humidity up 20% easily. This is in the mountains where it's drier than the desert in the winter.

They ‘cheat’ a little by lofting liquid water which then evaporates. We have a water softener and the cool mist humidifier left a smoke-like particulate floating in the air (i think it was either salt from the softener or minerals from the water)

Yes, that's the minerals in the water. Using distilled water prevents this.

I discovered this when doing a post-assembly indoor test of a Luftdaten air quality sensor I built[0]. I kept it running for few hours and then looked at the data, and saw some ridiculously high levels of PM2.5 and PM5 in the evening. I've decided to investigate it. Over the next two days, I figured out that the increased levels happen at times when our air humidifier is running, which led me to discover that those ultrasonic air humidifiers essentially atomize everything that was mixed with/dissolved in the water - and we were using filtered tap water with ours. With distilled water in the humidifier, the sensor did not show increased particulate levels.

We've mostly stopped using the humidifier now, because I can't find a source of distilled water that doesn't involve buying plastic bottles.

[0] - https://luftdaten.info/en/home-en/

I've encountered the same issue (high plastic bottle waste along with high cost). Short of boiling your own water outdoors to avoid polluting the indoor air, it's challenging to find a source for bulk distilled water.

Boiling your water indoors will humidify the air.

Yes, and it will also release the impurities/minerals into the air, which is what we're trying to avoid by using distilled/boiled water.

I live in an area with very hard water (around 300ppm), and the evaporated minerals are very visible in the air (and it leaves a white residue on the surrounding area).

> I live in an area with very hard water (around 300ppm)

Tangential, but being curious how hard that was relative to mine led me to discover that Thames Water (i.e. only useful to anyone reading in London) has a pretty good page at [0] - a summary on the site itself but the PDF is really worth a look, lots of numbers. Maybe it's a regulatory requirement, but I wouldn't have expected it to be so easy to get so much information from them about my specific (it serves many districts in and around London with different sources and equipment) water supply.

[0]: https://www.thameswater.co.uk/help-and-advice/water-quality/...

It's actually quite common for water authorities to publish quite detailed analyses of the water they provide. Doing such analyses is a core competency of being a water authority and, since they are mostly publicly owned, then published for consumers, often at a fairly detailed level.

> water authority and, since they are mostly publicly owned

Not here:

https://en.wikipedia.org/wiki/United_Kingdom_water_companies

(E.g. Canada Pension Plan, Morgan Stanley, Hong Kong based investment trust)

As I said, it may be a regulatory (Ofwat) requirement, but it isn't just a public body doing right by its citizens.

Interesting anyway, not that much of it means anything to me. Though apparently if/when I try brewing beer again I should add some magnesium. (It even lists the range that's helpful as a yeast nutrient, and above which contributes unwanted taste.)

Boiling water will not get much of the minerals into the air. This is why distillation works.

Would filtering it first help with that?

Yes, my humidifier actually has filters you can buy, but it's a bit cost prohibitive (around $20/filter and with the hardness of the water they only last about 3 weeks).

I just use filtered water from my fridge or from my Brita. Haven't noticed any nasty build up in the humidifier or any hazy production. The larger Honeywell I use in the master bedroom is the top fill which is designed as filter free.

Rain is essentially distilled water (evaporation from terrestrial water bodies and then condensation in the atmosphere). It picks up some contaminants in the atmosphere and some dissolved gases when it condenses but it's going to be mostly free of minerals (i.e. not be hard). So collecting rain water is one source of bulk 'distilled water'.

Depending on where he lives, that might actually be illegal to do.[1]

[1] https://bestlifeonline.com/illegal-collect-rainwater/

We also have a air purifier that watches for particulate and they would battle each other constantly lol.

Moved to an evaporative humidifier, my air quality appliances now operate in peace.

Oooooh, so that is the cause of my apartment being hazy?! Just moved to a new place, air humidity can get around 10% and since I don't enjoy being tazed by my sofa I bought a small humidifier from Amazon, both I and my wife noticed what seems to be a cloud in our living room.

If it's a cool-mist type humidifier, definitely.

I grabbed an evaporative one from the local big box hardware store and zero 'smoke'. You should get some bacteriostat and you'll have to replace the paper elements every now and again, but it's way better.

This may also indicate insufficient air exchange (high CO2 level) in your bedroom.

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